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63c648c25f004bf4898cff72
2023-03-08T20:45:54.701Z
Help Fix Code
v1
null
#include <stdio.h> #include <stdlib.h> #include <string.h> #include <unistd.h> #include <sys/types.h> #include <sys/wait.h> #define MAXLINE 256 #define MAX_PASSWORD 10 #define SUCCESS "Password verified\n" #define INVALID "Invalid password\n" #define NO_USER "No such user\n" int main(void) { char user_id[MAXLINE]; char password[MAXLINE]; /* The user will type in a user name on one line followed by a password on the next. DO NOT add any prompts. The only output of this program will be one of the messages defined above. Please read the comments in validate carefully */ if(fgets(user_id, MAXLINE, stdin) == NULL) { perror("fgets"); exit(1); } if(fgets(password, MAXLINE, stdin) == NULL) { perror("fgets"); exit(1); } // TODO if(strlen(password) > MAX_PASSWORD){ printf("password too long"); exit(1); // password too long }else if(strlen(user_id) > MAX_PASSWORD){ printf("user_id too long"); // user_id too long exit(1); } int pid = fork(); if(pid == 0){ char *arg_Ptr[5]; arg_Ptr[0] = "validate.c"; arg_Ptr[1] = user_id; arg_Ptr[2] = password; arg_Ptr[3] = NULL; execv(./validate.c, arg_Ptr); } int status; if (wait(&status) >= 0){ if (WEXITED(status)){ exit(WEXITSTATUS(status)); } } return 0; }
checkpasswd.c creates a new process to run the validate.c program
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63c648c25f004bf4898cff72
2023-03-08T20:47:26.660Z
Help Fix Code
v1
null
#include <stdio.h> #include <stdlib.h> #include <string.h> #include <unistd.h> #include <sys/types.h> #include <sys/wait.h> #define MAXLINE 256 #define MAX_PASSWORD 10 #define SUCCESS "Password verified\n" #define INVALID "Invalid password\n" #define NO_USER "No such user\n" int main(void) { char user_id[MAXLINE]; char password[MAXLINE]; /* The user will type in a user name on one line followed by a password on the next. DO NOT add any prompts. The only output of this program will be one of the messages defined above. Please read the comments in validate carefully */ if(fgets(user_id, MAXLINE, stdin) == NULL) { perror("fgets"); exit(1); } if(fgets(password, MAXLINE, stdin) == NULL) { perror("fgets"); exit(1); } // TODO if(strlen(password) > MAX_PASSWORD){ printf("password too long"); exit(1); // password too long }else if(strlen(user_id) > MAX_PASSWORD){ printf("user_id too long"); // user_id too long exit(1); } int pid = fork(); if(pid == 0){ char *arg_Ptr[5]; arg_Ptr[0] = "validate.c"; arg_Ptr[1] = user_id; arg_Ptr[2] = password; arg_Ptr[3] = NULL; execv(./validate, arg_Ptr); } int status; if (wait(&status) >= 0){ if (WEXITED(status)){ exit(WEXITSTATUS(status)); } } return 0; }
checkpasswd.c creates a new process to run the validate.c program
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63c648c25f004bf4898cff72
2023-03-08T20:55:41.250Z
Help Fix Code
v1
null
#include <stdio.h> #include <stdlib.h> #include <string.h> #include <unistd.h> #include <sys/types.h> #include <sys/wait.h> #define MAXLINE 256 #define MAX_PASSWORD 10 #define SUCCESS "Password verified\n" #define INVALID "Invalid password\n" #define NO_USER "No such user\n" int main(void) { char user_id[MAXLINE]; char password[MAXLINE]; /* The user will type in a user name on one line followed by a password on the next. DO NOT add any prompts. The only output of this program will be one of the messages defined above. Please read the comments in validate carefully */ if(fgets(user_id, MAXLINE, stdin) == NULL) { perror("fgets"); exit(1); } if(fgets(password, MAXLINE, stdin) == NULL) { perror("fgets"); exit(1); } // TODO if(strlen(password) > MAX_PASSWORD){ printf("password too long"); exit(1); // password too long }else if(strlen(user_id) > MAX_PASSWORD){ printf("user_id too long"); // user_id too long exit(1); } int pid = fork(); if(pid == 0){ char *arg_Ptr[4]; arg_Ptr[0] = "validate.c"; arg_Ptr[1] = user_id; arg_Ptr[2] = password; arg_Ptr[3] = NULL; execv(./validate.c, arg_Ptr); } int status; if (wait(&status) >= 0){ if (WEXITED(status)){ exit(WEXITSTATUS(status)); } } return 0; }
checkpasswd.c creates a new process to run the validate.c program
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63c648c25f004bf4898cff72
2023-03-08T21:33:30.242Z
Question from Code
v1
how to get the file path from validate.c
#include <stdio.h> #include <stdlib.h> #include <string.h> #include <unistd.h> #include <sys/types.h> #include <sys/wait.h> #define MAXLINE 256 #define MAX_PASSWORD 10 #define SUCCESS "Password verified\n" #define INVALID "Invalid password\n" #define NO_USER "No such user\n" int main(void) { char user_id[MAXLINE]; char password[MAXLINE]; /* The user will type in a user name on one line followed by a password on the next. DO NOT add any prompts. The only output of this program will be one of the messages defined above. Please read the comments in validate carefully */ if(fgets(user_id, MAXLINE, stdin) == NULL) { perror("fgets"); exit(1); } if(fgets(password, MAXLINE, stdin) == NULL) { perror("fgets"); exit(1); } // TODO if(strlen(password) > MAX_PASSWORD){ printf("password too long"); exit(1); // password too long }else if(strlen(user_id) > MAX_PASSWORD){ printf("user_id too long"); // user_id too long exit(1); } int pid = fork(); if(pid == 0){ // child char *arg_Ptr[4]; arg_Ptr[0] = "validate.c"; arg_Ptr[1] = user_id; arg_Ptr[2] = password; arg_Ptr[3] = NULL; execv(validate.c, arg_Ptr); } int status; if (wait(&status) >= 0){ if (WEXITED){ exit(WEXITSTATUS(status)); } } return 0; }
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63c648c25f004bf4898cff72
2023-03-08T21:34:10.025Z
Question from Code
v1
how to get the file path from the file validate.c?
#include <stdio.h> #include <stdlib.h> #include <string.h> #include <unistd.h> #include <sys/types.h> #include <sys/wait.h> #define MAXLINE 256 #define MAX_PASSWORD 10 #define SUCCESS "Password verified\n" #define INVALID "Invalid password\n" #define NO_USER "No such user\n" int main(void) { char user_id[MAXLINE]; char password[MAXLINE]; /* The user will type in a user name on one line followed by a password on the next. DO NOT add any prompts. The only output of this program will be one of the messages defined above. Please read the comments in validate carefully */ if(fgets(user_id, MAXLINE, stdin) == NULL) { perror("fgets"); exit(1); } if(fgets(password, MAXLINE, stdin) == NULL) { perror("fgets"); exit(1); } // TODO if(strlen(password) > MAX_PASSWORD){ printf("password too long"); exit(1); // password too long }else if(strlen(user_id) > MAX_PASSWORD){ printf("user_id too long"); // user_id too long exit(1); } int pid = fork(); if(pid == 0){ // child char *arg_Ptr[4]; arg_Ptr[0] = "validate.c"; arg_Ptr[1] = user_id; arg_Ptr[2] = password; arg_Ptr[3] = NULL; execv(validate.c, arg_Ptr); } int status; if (wait(&status) >= 0){ if (WEXITED){ exit(WEXITSTATUS(status)); } } return 0; }
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63c648c25f004bf4898cff72
2023-03-08T23:24:45.094Z
Help Fix Code
v1
null
#include <stdio.h> #include <stdlib.h> #include <string.h> #include <unistd.h> #include <sys/types.h> #include <sys/wait.h> #define MAXLINE 256 #define MAX_PASSWORD 10 #define SUCCESS "Password verified\n" #define INVALID "Invalid password\n" #define NO_USER "No such user\n" int main(void) { char user_id[MAXLINE]; char password[MAXLINE]; /* The user will type in a user name on one line followed by a password on the next. DO NOT add any prompts. The only output of this program will be one of the messages defined above. Please read the comments in validate carefully */ if(fgets(user_id, MAXLINE, stdin) == NULL) { perror("fgets"); exit(1); } if(fgets(password, MAXLINE, stdin) == NULL) { perror("fgets"); exit(1); } // TODO if(strlen(password) > MAX_PASSWORD){ printf("password too long"); exit(1); // password too long }else if(strlen(user_id) > MAX_PASSWORD){ printf("user_id too long"); // user_id too long exit(1); } int pid = fork(); if(pid == 0){ // child char *arg_Ptr[4]; arg_Ptr[0] = "validate.c"; arg_Ptr[1] = user_id; arg_Ptr[2] = password; arg_Ptr[3] = NULL; execvp("validate.c", arg_Ptr); } int status; if (wait(&status) >= 0){ if (WEXITED){ exit(WEXITSTATUS(status)); } } return 0; }
reads a user id and password from stdin, creates a new process to run the validate program, sends it the user id and password, and prints a message to stdout reporting whether the validation is successful.
null
63c648c25f004bf4898cff72
2023-03-08T23:30:37.501Z
Help Fix Code
v1
null
#include <stdio.h> #include <stdlib.h> #include <string.h> #include <unistd.h> #include <sys/types.h> #include <sys/wait.h> #define MAXLINE 256 #define MAX_PASSWORD 10 #define SUCCESS "Password verified\n" #define INVALID "Invalid password\n" #define NO_USER "No such user\n" int main(void) { char user_id[MAXLINE]; char password[MAXLINE]; /* The user will type in a user name on one line followed by a password on the next. DO NOT add any prompts. The only output of this program will be one of the messages defined above. Please read the comments in validate carefully */ if(fgets(user_id, MAXLINE, stdin) == NULL) { perror("fgets"); exit(1); } if(fgets(password, MAXLINE, stdin) == NULL) { perror("fgets"); exit(1); } // TODO if(strlen(user_id) > MAX_PASSWORD){ printf("user_id too long"); // user_id too long exit(1); }else if(strlen(password) > MAX_PASSWORD){ printf("password too long"); exit(1); // password too long } int pid = fork(); if(pid == 0){ // child char *arg_Ptr[] = {"./validate.c", user_id, password, NULL}; // char *arg_Ptr[4]; // arg_Ptr[0] = "./validate.c"; // arg_Ptr[1] = user_id; // arg_Ptr[2] = password; // arg_Ptr[3] = NULL; execvp("validate.c", arg_Ptr); } int status; if (wait(&status) >= 0){ if (WEXITED){ exit(WEXITSTATUS(status)); } } return 0; }
reads a user id and password from stdin, creates a new process to run the validate program, sends it the user id and password, and prints a message to stdout reporting whether the validation is successful.
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63c648c25f004bf4898cff72
2023-03-09T00:20:14.020Z
Help Fix Code
v1
null
#include <stdio.h> #include <stdlib.h> #include <string.h> #include <unistd.h> #include <sys/types.h> #include <sys/wait.h> #define MAXLINE 256 #define MAX_PASSWORD 10 #define SUCCESS "Password verified\n" #define INVALID "Invalid password\n" #define NO_USER "No such user\n" int main(void) { char user_id[MAXLINE]; char password[MAXLINE]; /* The user will type in a user name on one line followed by a password on the next. DO NOT add any prompts. The only output of this program will be one of the messages defined above. Please read the comments in validate carefully */ if(fgets(user_id, MAXLINE, stdin) == NULL) { perror("fgets"); exit(1); } if(fgets(password, MAXLINE, stdin) == NULL) { perror("fgets"); exit(1); } // TODO if(strlen(user_id) > MAX_PASSWORD){ printf("user_id too long"); // user_id too long exit(1); }else if(strlen(password) > MAX_PASSWORD){ printf("password too long"); exit(1); // password too long } int pid = fork(); if(pid == 0){ // child char *arg_Ptr[] = {"./validate", user_id, password, NULL}; // int dup2(int "validate.c", int newfd); execvp(arg_Ptr[0], arg_Ptr); } int status; if (wait(&status) >= 0){ if (WEXITED){ exit(WEXITSTATUS(status)); } } return 0; }
reads a user id and password from stdin, creates a new process to run the validate program, sends it the user id and password, and prints a message to stdout reporting whether the validation is successful.
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63c648c25f004bf4898cff72
2023-03-14T05:09:40.316Z
Question from Code
v2
What does the program print to stderr if the user presses Ctrl+C at the moment when the program is at position C?
int x = 5; void handler(int sig) { x += 3; fprintf(stderr, "inside %d ", x); } int main() { fprintf(stderr, "start "); // POSITION A struct sigaction act; act.sa_handler = handler; act.sa_flags = 0; sigemptyset(&act.sa_mask); sigaction(SIGINT, &act, NULL); // POSITION B x += 2; // POSITION C fprintf(stderr, "outside %d", x); return 0; }
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63c648c25f004bf4898cff72
2023-03-14T05:13:14.789Z
Question from Code
v2
What does the program print to stderr if the user presses Ctrl+C at the moment when the program is at position B?
int x = 5; void handler(int sig) { x += 3; fprintf(stderr, "inside %d ", x); } int main() { fprintf(stderr, "start "); // POSITION A struct sigaction act; act.sa_handler = handler; act.sa_flags = 0; sigemptyset(&act.sa_mask); sigaction(SIGINT, &act, NULL); // POSITION B x += 2; // POSITION C fprintf(stderr, "outside %d", x); return 0; }
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63c648c25f004bf4898cff72
2023-03-14T05:16:20.257Z
Question from Code
v2
What does the program print to stderr if the user presses Ctrl+C at the moment when the program is at position C?
int x = 5; void handler(int sig) { x += 3; fprintf(stderr, "inside %d ", x); } int main() { fprintf(stderr, "start "); // POSITION A struct sigaction act; act.sa_handler = handler; act.sa_flags = 0; sigemptyset(&act.sa_mask); sigaction(SIGINT, &act, NULL); // POSITION B x += 2; // POSITION C fprintf(stderr, "outside %d", x); return 0; }
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63c648c25f004bf4898cff72
2023-03-15T15:26:08.406Z
Help Write Code
v2
null
null
null
fgets skip empty line
63c648c25f004bf4898cff72
2023-03-15T16:10:30.006Z
General Question
v2
what is the value of fgets when it reads an empty line
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63c648c25f004bf4898cff72
2023-03-15T16:13:19.904Z
General Question
v2
what is the value of fgets when it reads a tab
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63c648c25f004bf4898cff72
2023-03-15T16:25:08.698Z
General Question
v2
does the value of fgets have a null terminator at the end
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63c648c25f004bf4898cff72
2023-03-17T20:18:38.628Z
Help Fix Code
v2
In an infinite loop, read an int from a random location in the file, * and print it to stderr.
/* The purpose of this program is to practice writing signal handling * functions and observing the behaviour of signals. */ #include <stdio.h> #include <signal.h> #include <stdlib.h> #include <unistd.h> #include <sys/time.h> /* Message to print in the signal handling function. */ #define MESSAGE "%ld reads were done in %ld seconds.\n" /* Global variables to store number of read operations and seconds elapsed. */ long num_reads, seconds; /* The first command-line argument is the number of seconds to set a timer to run. * The second argument is the name of a binary file containing 100 ints. * Assume both of these arguments are correct. */ int main(int argc, char **argv) { if (argc != 3) { fprintf(stderr, "Usage: time_reads s filename\n"); exit(1); } seconds = strtol(argv[1], NULL, 10); FILE *fp; if ((fp = fopen(argv[2], "r")) == NULL) { perror("fopen"); exit(1); } /* In an infinite loop, read an int from a random location in the file, * and print it to stderr. */ for (;;) { int offset = rand() % 100; int read_num; fseek(fp, offset, SEEK_CUR); fread(&read_num, sizeof(int), 1, fp); printf("%d", read_num); } return 1; // something is wrong if we ever get here! }
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63c648c25f004bf4898cff72
2023-03-17T20:20:19.410Z
Help Fix Code
v2
In an infinite loop, read an int from a random location in the file, * and print it to stderr.
for (;;) { int offset = rand() % 100; int read_num; fseek(fp, offset, SEEK_CUR); fread(&read_num, sizeof(int), 1, fp); printf("%d", read_num); }
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63c648c25f004bf4898cff72
2023-03-17T20:24:39.382Z
Help Fix Code
v2
In an infinite loop, read an int from a random location in the file, and print it to stderr.
for (;;) { int offset = rand() % 100; int read_num[5]; fseek(fp, offset, SEEK_CUR); fread(&read_num, sizeof(int), 1, fp); fprintf(sterr, "%d", read_num); }
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63c648c25f004bf4898cff72
2023-03-17T20:27:41.933Z
Help Fix Code
v2
In an infinite loop, read an int from a random location in the file, and print it to stderr.
for (;;) { int offset = rand() % 100; int read_num; fseek(fp, offset, SEEK_CUR); fread(&read_num, sizeof(int), 1, fp); fprintf(sterr, "%d", read_num); }
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63c648c25f004bf4898cff72
2023-03-17T20:38:21.245Z
Help Write Code
v2
null
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Now, use sigactionLinks to an external site. to add a signal handler to your program. Start with something simple that just prints a message to standard out and exits (with termination code 0) when it receives a SIGPROF.
63c648c25f004bf4898cff72
2023-03-17T20:45:38.614Z
Help Fix Code
v2
Now, use sigactionLinks to add a signal handler to your program. Start with something simple that just prints a message to standard out and exits (with termination code 0) when it receives a SIGPROF.
int main(int argc, char **argv) { if (argc != 3) { fprintf(stderr, "Usage: time_reads s filename\n"); exit(1); } seconds = strtol(argv[1], NULL, 10); FILE *fp; if ((fp = fopen(argv[2], "r")) == NULL) { perror("fopen"); exit(1); } struct sigaction newact; newact.sa_handler = handler; newact.sa_flags = 0; sigemptyset(&newact.sa_mask); sigaction(SIGINT, &newact, NULL); /* In an infinite loop, read an int from a random location in the file, * and print it to stderr. */ for (;;) { int offset = rand() % 100; int read_num; fseek(fp, offset, SEEK_SET); fread(&read_num, sizeof(int), 1, fp); fprintf(stderr, "%d", read_num); } return 1; // something is wrong if we ever get here! }
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63c648c25f004bf4898cff72
2023-03-17T20:47:40.599Z
Help Fix Code
v2
use sigactionLinks to add a signal handler to your program. Start with something simple that just prints a message to standard out and exits (with termination code 0) when it receives a SIGPROF.
void handler(int sig){ printf("SIGPROF received"); exit(0); } int main(int argc, char **argv) { struct sigaction newact; newact.sa_handler = handler; newact.sa_flags = 0; sigemptyset(&newact.sa_mask); sigaction(SIGINT, &newact, NULL); /* In an infinite loop, read an int from a random location in the file, * and print it to stderr. */ for (;;) { int offset = rand() % 100; int read_num; fseek(fp, offset, SEEK_SET); fread(&read_num, sizeof(int), 1, fp); fprintf(stderr, "%d", read_num); } return 1; // something is wrong if we ever get here! }
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63c648c25f004bf4898cff72
2023-03-17T20:58:29.546Z
Help Write Code
v2
null
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null
Add code to set up a timer (using setitimer) for s seconds (where s is obtained from the command line). You shouldn't use real time, since your results will be affected if your system is busy. Instead, use ITIMER_PROF to make the itimer send a SIGPROF
63c648c25f004bf4898cff72
2023-03-17T21:23:26.221Z
Help Fix Code
v2
Add code to set up a timer (using setitimer) for s seconds (where s is obtained from the command line). You shouldn't use real time, since your results will be affected if your system is busy. Instead, use ITIMER_PROF to make the itimer send a SIGPROF
struct itimerval it_val; struct timeval interval_next; struct timeval interval_current; interval_next.tv_sec = 0; interval_next.tv_usec = 0; interval_current.tv_sec = seconds; interval_current.tv_usec = 0; it_val.it_interval = interval_next; it_val.it_value = interval_current; setitimer(ITIMER_PROF, &it_val, NULL);
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63c648c25f004bf4898cff72
2023-03-17T21:29:53.347Z
Help Fix Code
v2
Add code to set up a timer (using setitimer) for s seconds (where s is obtained from the command line). You shouldn't use real time, since your results will be affected if your system is busy. Instead, use ITIMER_PROF to make the itimer send a SIGPROF
/* The purpose of this program is to practice writing signal handling * functions and observing the behaviour of signals. */ #include <stdio.h> #include <signal.h> #include <stdlib.h> #include <unistd.h> #include <sys/time.h> /* Message to print in the signal handling function. */ #define MESSAGE "%ld reads were done in %ld seconds.\n" /* Global variables to store number of read operations and seconds elapsed. */ long num_reads, seconds; void handler(int sig){ fprintf(stdout, MESSAGE, num_reads, seconds); exit(0); } /* The first command-line argument is the number of seconds to set a timer to run. * The second argument is the name of a binary file containing 100 ints. * Assume both of these arguments are correct. */ int main(int argc, char **argv) { if (argc != 3) { fprintf(stderr, "Usage: time_reads s filename\n"); exit(1); } seconds = strtol(argv[1], NULL, 10); FILE *fp; if ((fp = fopen(argv[2], "r")) == NULL) { perror("fopen"); exit(1); } struct sigaction newact; newact.sa_handler = handler; newact.sa_flags = 0; sigemptyset(&newact.sa_mask); sigaction(SIGPROF, &newact, NULL); struct itimerval it_val; struct timeval interval_next; struct timeval interval_current; interval_next.tv_sec = 0; interval_next.tv_usec = 0; interval_current.tv_sec = seconds; interval_current.tv_usec = 0; it_val.it_interval = interval_next; it_val.it_value = interval_current; if (setitimer(ITIMER_REAL, &it_val, NULL) == -1) { perror("setitimer"); exit(1); } /* In an infinite loop, read an int from a random location in the file, * and print it to stderr. */ for (;;) { int offset = rand() % 100; int read_num; fseek(fp, offset, SEEK_SET); fread(&read_num, sizeof(int), 1, fp); fprintf(stderr, "%d", read_num); } return 1; // something is wrong if we ever get here! }
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63c648c25f004bf4898cff72
2023-03-17T21:33:12.671Z
Help Fix Code
v2
Add code to set up a timer (using setitimer) for s seconds (where s is obtained from the command line). You shouldn't use real time, since your results will be affected if your system is busy. Instead, use ITIMER_PROF to make the itimer send a SIGPROF
/* The purpose of this program is to practice writing signal handling * functions and observing the behaviour of signals. */ #include <stdio.h> #include <signal.h> #include <stdlib.h> #include <unistd.h> #include <sys/time.h> /* Message to print in the signal handling function. */ #define MESSAGE "%ld reads were done in %ld seconds.\n" /* Global variables to store number of read operations and seconds elapsed. */ long num_reads, seconds; void handler(int sig){ fprintf(stdout, MESSAGE, num_reads, seconds); exit(0); } /* The first command-line argument is the number of seconds to set a timer to run. * The second argument is the name of a binary file containing 100 ints. * Assume both of these arguments are correct. */ int main(int argc, char **argv) { if (argc != 3) { fprintf(stderr, "Usage: time_reads s filename\n"); exit(1); } seconds = strtol(argv[1], NULL, 10); FILE *fp; if ((fp = fopen(argv[2], "r")) == NULL) { perror("fopen"); exit(1); } struct sigaction newact; newact.sa_handler = handler; newact.sa_flags = 0; sigemptyset(&newact.sa_mask); sigaction(SIGPROF, &newact, NULL); struct itimerval it_val; struct timeval interval_next; struct timeval interval_current; interval_next.tv_sec = 0; interval_next.tv_usec = 0; interval_current.tv_sec = seconds; interval_current.tv_usec = 0; it_val.it_interval = interval_next; it_val.it_value = interval_current; if (setitimer(ITIMER_PROF, &it_val, NULL) == -1) { perror("setitimer"); exit(1); } /* In an infinite loop, read an int from a random location in the file, * and print it to stderr. */ for (;;) { int offset = rand() % 100; int read_num; fseek(fp, offset, SEEK_SET); fread(&read_num, sizeof(int), 1, fp); fprintf(stderr, "%d", read_num); } return 1; // something is wrong if we ever get here! }
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63c648c25f004bf4898cff72
2023-03-21T02:31:40.014Z
General Question
v2
If x is set to 77 (0100 1101 in binary), what is the value of x << 2 in binary?
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63c648c25f004bf4898cff72
2023-03-21T02:54:34.491Z
General Question
v2
Which function would you use to find the IP address of a machine, given its name?
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63c648c25f004bf4898cff72
2023-03-24T19:15:10.495Z
General Question
v2
how to update inbuf
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63c648c25f004bf4898cff72
2023-03-24T19:19:00.113Z
Question from Code
v2
am I updating the inbuf right?
#include <arpa/inet.h> #include <stdio.h> #include <stdlib.h> #include <string.h> #include <unistd.h> #include "socket.h" #ifndef PORT #define PORT 30000 #endif #define BUFSIZE 30 int find_network_newline(const char *buf, int n); int main() { // This line causes stdout not to be buffered. // Don't change this! Necessary for autotesting. setbuf(stdout, NULL); struct sockaddr_in *self = init_server_addr(PORT); int listenfd = set_up_server_socket(self, 5); while (1) { int fd = accept_connection(listenfd); if (fd < 0) { continue; } // Receive messages char buf[BUFSIZE] = {'\0'}; int inbuf = 0; // How many bytes currently in buffer? int room = sizeof(buf); // How many bytes remaining in buffer? char *after = buf; // Pointer to position after the data in buf int nbytes; while ((nbytes = read(fd, after, room)) > 0) { // Step 1: update inbuf (how many bytes were just added?) inbuf = BUFSIZE - room; int where; } close(fd); printf("The connection is now closed ...\n"); } free(self); close(listenfd); return 0; }
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63c648c25f004bf4898cff72
2023-03-24T19:20:14.242Z
Question from Code
v2
am I returning the correct value?
int find_network_newline(const char *buf, int n) { for (int i = 0; i < (n - 1); i++) { if (buf[i] == '\r' && buf[i + 1] == '\n') { return 1 + (i + 1); } } return -1; }
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63c648c25f004bf4898cff72
2023-03-24T19:22:01.985Z
Question from Code
v2
am I printing the correct value, where the print statments Output the full line, not including the "\r\n"
while ((where = find_network_newline(buf, inbuf)) > 0) { // where is now the index into buf immediately after // the first network newline // Step 3: Okay, we have a full line. // Output the full line, not including the "\r\n", // using print statement below. // Be sure to put a '\0' in the correct place first; // otherwise you'll get junk in the output. buf[where - 1] = '\0'; printf("Next message: %s\n", buf);
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63c648c25f004bf4898cff72
2023-03-24T19:23:15.116Z
Help Fix Code
v2
Output the full line, not including the "\r\n"
while ((where = find_network_newline(buf, inbuf)) > 0) { // where is now the index into buf immediately after // the first network newline // Step 3: Okay, we have a full line. // Output the full line, not including the "\r\n", // using print statement below. // Be sure to put a '\0' in the correct place first; // otherwise you'll get junk in the output. buf[where-1] = '\0'; printf("Next message: %s\n", buf);
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63c648c25f004bf4898cff72
2023-03-24T19:38:34.427Z
Question from Code
v2
am i updating inbuf and removing the full line from the buffer right?
#define BUFSIZE 30 int find_network_newline(const char *buf, int n); int main() { setbuf(stdout, NULL); struct sockaddr_in *self = init_server_addr(PORT); int listenfd = set_up_server_socket(self, 5); while (1) { int fd = accept_connection(listenfd); if (fd < 0) { continue; } // Receive messages char buf[BUFSIZE] = {'\0'}; int inbuf = 0; // How many bytes currently in buffer? int room = sizeof(buf); // How many bytes remaining in buffer? char *after = buf; // Pointer to position after the data in buf int nbytes; while ((nbytes = read(fd, after, room)) > 0) { inbuf += nbytes; int where; while ((where = find_network_newline(buf, inbuf)) > 0) { buf[where - 1] = '\0'; printf("Next message: %s\n", buf); // Step 4: update inbuf and remove the full line from the buffer // There might be stuff after the line, so don't just do inbuf = 0. // You want to move the stuff after the full line to the beginning // of the buffer. A loop can do it, or you can use memmove. // memmove(destination, source, number_of_bytes) int number_of_bytes = strlen(buf) - inbuf; char move_this[number_of_bytes]; int move_this_index = 0; int new_after_index = 0; int after_after = -1; for (int i = (where + 1); i < strlen(buf); i++) { if (buf[i] == &after) { after_after = 0; } if (after_after == -1) { new_after_index += 1; } move_this[move_this_index] = buf[i]; move_this_index += 1; } memmove(buf, move_this, number_of_bytes); inbuf = strlen(buf) - new_after_index; } } close(fd); printf("The connection is now closed ...\n"); } free(self); close(listenfd); return 0; }
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63c648c25f004bf4898cff72
2023-03-24T19:43:41.430Z
Question from Code
v2
am I updating after and room correctly?
#define BUFSIZE 30 int find_network_newline(const char *buf, int n); int main() { // This line causes stdout not to be buffered. // Don't change this! Necessary for autotesting. setbuf(stdout, NULL); struct sockaddr_in *self = init_server_addr(PORT); int listenfd = set_up_server_socket(self, 5); while (1) { int fd = accept_connection(listenfd); if (fd < 0) { continue; } // Receive messages char buf[BUFSIZE] = {'\0'}; int inbuf = 0; // How many bytes currently in buffer? int room = sizeof(buf); // How many bytes remaining in buffer? char *after = buf; // Pointer to position after the data in buf int nbytes; while ((nbytes = read(fd, after, room)) > 0) { inbuf += nbytes; int where; while ((where = find_network_newline(buf, inbuf)) > 0) { buf[where - 1] = '\0'; printf("Next message: %s\n", buf); int number_of_bytes = inbuf - (where + 1); char move_this[number_of_bytes]; memmove(buf, &buf[where + 1], number_of_bytes); inbuf = number_of_bytes; } // Step 5: update after and room, in preparation for the next read. after = buf[strlen(buf) - inbuf]; room = strlen(buf) - inbuf; }
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63c648c25f004bf4898cff72
2023-03-28T03:39:09.172Z
General Question
v2
shell programming, Variables width and height have been initialized. Calculate the area of a rectangle using width and height, and assign the resulting value to a variable named area.
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63c648c25f004bf4898cff72
2023-03-28T03:55:25.973Z
General Question
v2
man page for test
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63c648c25f004bf4898cff72
2023-03-28T04:02:35.717Z
General Question
v2
If a command produces output that we want to discard, to which file do we redirect it? Provide the complete path.
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63c648c25f004bf4898cff72
2023-03-28T17:38:48.938Z
Question from Code
v2
Task 1: The task is to There are now two different types of input that we could receive: a username, or a message. If we have not yet received the username, then we should copy buf to username. Otherwise, the input will be a message to write to the socket. How do I write to the socket?
int read_from(int client_index, struct sockname *users) { int fd = users[client_index].sock_fd; char buf[BUF_SIZE + 1]; int num_read = read(fd, &buf, BUF_SIZE); buf[num_read] = '\0'; if (users[client_index].username = NULL) { users[client_index].username = malloc(sizeof(char) * (strlen(buf))); strcpy(users[client_index].username, buf); } if (num_read == 0 || write(fd, buf, strlen(buf)) != strlen(buf)) { users[client_index].sock_fd = -1; return fd; } return 0; }
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63c648c25f004bf4898cff72
2023-03-28T20:24:22.817Z
Question from Code
v2
Task 1: There are now two different types of input that we could receive: a username, or a message. If we have not yet received the username, then we should copy buf to username. Otherwise, the input will be a message to write to the socket. Did I complete task 1 properly?
int read_from(int client_index, struct sockname *users) { int fd = users[client_index].sock_fd; char buf[BUF_SIZE + 1]; int num_read = read(fd, &buf, BUF_SIZE); buf[num_read] = '\0'; if (users[client_index].username = NULL) { users[client_index].username = malloc(sizeof(char) * (strlen(buf))); strcpy(users[client_index].username, buf); } else { int num_written = write(users[client_index].sock_fd, buf, strlen(buf)); if (num_written != strlen(buf)) { printf("Error"); return -1; } } if (num_read == 0 || write(fd, buf, strlen(buf)) != strlen(buf)) { users[client_index].sock_fd = -1; return fd; } return 0; }
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63c648c25f004bf4898cff72
2023-03-28T20:26:15.928Z
Question from Code
v2
Task 1: There are now two different types of input that we could receive: a username, or a message. If we have not yet received the username, then we should copy buf to username. Otherwise, the input will be a message to write to the socket. Did I complete task 1 properly?
int read_from(int client_index, struct sockname *users) { int fd = users[client_index].sock_fd; char buf[BUF_SIZE + 1]; int num_read = read(fd, &buf, BUF_SIZE); buf[num_read] = '\0'; if (users[client_index].username == NULL) { users[client_index].username = malloc(sizeof(char) * (strlen(buf))); strcpy(users[client_index].username, buf); } else { int num_written = write(users[client_index].sock_fd, buf, strlen(buf)); if (num_written != strlen(buf)) { printf("Error"); return -1; } } if (num_read == 0 || write(fd, buf, strlen(buf)) != strlen(buf)) { users[client_index].sock_fd = -1; return fd; } return 0; }
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63c648c25f004bf4898cff72
2023-03-28T20:27:05.804Z
Question from Code
v2
How do I change the code to broadcast to all connected clients
int read_from(int client_index, struct sockname *users) { int fd = users[client_index].sock_fd; char buf[BUF_SIZE + 1]; int num_read = read(fd, &buf, BUF_SIZE); buf[num_read] = '\0'; if (users[client_index].username == NULL) { users[client_index].username = malloc(sizeof(char) * (strlen(buf))); strcpy(users[client_index].username, buf); } else { int num_written = write(users[client_index].sock_fd, buf, strlen(buf)); if (num_written != strlen(buf)) { printf("Error"); return -1; } } if (num_read == 0 || write(fd, buf, strlen(buf)) != strlen(buf)) { users[client_index].sock_fd = -1; return fd; } return 0; }
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63c648c25f004bf4898cff72
2023-03-31T20:15:44.450Z
Question from Code
v2
What part of the code do I have to change to broadcast to all connected clients?
int read_from(int client_index, struct sockname *users) { int fd = users[client_index].sock_fd; char buf[BUF_SIZE + 1]; int num_read = read(fd, &buf, BUF_SIZE); buf[num_read] = '\0'; if (users[client_index].username == NULL) { users[client_index].username = malloc(sizeof(char) * (strlen(buf))); strcpy(users[client_index].username, buf); } else { int num_written = write(users[client_index].sock_fd, buf, strlen(buf)); if (num_written != strlen(buf)) { printf("Error"); return -1; } } if (num_read == 0 || write(fd, buf, strlen(buf)) != strlen(buf)) { users[client_index].sock_fd = -1; return fd; } return 0; }
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63c648c25f004bf4898cff72
2023-03-31T20:23:32.817Z
Question from Code
v2
did i correctly change the code to broadcast to all connected clients?
int read_from(int client_index, struct sockname *users) { int fd = users[client_index].sock_fd; char buf[BUF_SIZE + 1]; int num_read = read(fd, &buf, BUF_SIZE); buf[num_read] = '\0'; if (users[client_index].username == NULL) { users[client_index].username = malloc(sizeof(char) * (strlen(buf))); strcpy(users[client_index].username, buf); } else { for (int i = 0; i < MAX_CONNECTIONS; i++) { if users [client_index].sock_fd == -1 : { int num_written = write(users[client_index].sock_fd, buf, strlen(buf)); if (num_written != strlen(buf)) { printf("Error"); return -1; } } } } if (num_read == 0 || write(fd, buf, strlen(buf)) != strlen(buf)) { users[client_index].sock_fd = -1; return fd; } return 0; }
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63c648c25f004bf4898cff72
2023-03-31T20:26:14.054Z
Question from Code
v2
did i correctly change the code to broadcast to all connected clients?
#ifndef PORT #define PORT 30000 #endif #define MAX_BACKLOG 5 #define MAX_CONNECTIONS 12 #define BUF_SIZE 128 int read_from(int client_index, struct sockname *users) { int fd = users[client_index].sock_fd; char buf[BUF_SIZE + 1]; int num_read = read(fd, &buf, BUF_SIZE); buf[num_read] = '\0'; if (users[client_index].username == NULL) { users[client_index].username = malloc(sizeof(char) * (strlen(buf))); strcpy(users[client_index].username, buf); } else { for (int i = 0; i < MAX_CONNECTIONS - 1; i++) { if (users[client_index].sock_fd == -1 && client_index != i) { int num_written = write(users[client_index].sock_fd, buf, strlen(buf)); if (num_written != strlen(buf)) { printf("Error"); return -1; } } } } if (num_read == 0 || write(fd, buf, strlen(buf)) != strlen(buf)) { users[client_index].sock_fd = -1; return fd; } return 0; }
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63c648c25f004bf4898cff72
2023-03-31T20:27:36.396Z
Question from Code
v2
did i correctly change the code to broadcast to all connected clients?
#ifndef PORT #define PORT 30000 #endif #define MAX_BACKLOG 5 #define MAX_CONNECTIONS 12 #define BUF_SIZE 128 int read_from(int client_index, struct sockname *users) { int fd = users[client_index].sock_fd; char buf[BUF_SIZE + 1]; int num_read = read(fd, &buf, BUF_SIZE); buf[num_read] = '\0'; if (users[client_index].username == NULL) { users[client_index].username = malloc(sizeof(char) * (strlen(buf))); strcpy(users[client_index].username, buf); } else { for (int i = 0; i < MAX_CONNECTIONS - 1; i++) { if (users[client_index].sock_fd != -1 && client_index != i) { int num_written = write(users[client_index].sock_fd, buf, strlen(buf)); if (num_written != strlen(buf)) { printf("Error"); return -1; } } } } if (num_read == 0 || write(fd, buf, strlen(buf)) != strlen(buf)) { users[client_index].sock_fd = -1; return fd; } return 0; }
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63c648c25f004bf4898cff72
2023-03-31T20:30:26.177Z
Question from Code
v2
did i correctly change the code to broadcast to all connected clients?
#ifndef PORT #define PORT 30000 #endif #define MAX_BACKLOG 5 #define MAX_CONNECTIONS 12 #define BUF_SIZE 128 int read_from(int client_index, struct sockname *users) { int fd = users[client_index].sock_fd; char buf[BUF_SIZE + 1]; int num_read = read(fd, &buf, BUF_SIZE); buf[num_read] = '\0'; if (users[client_index].username == NULL) { users[client_index].username = malloc(sizeof(char) * (strlen(buf))); strcpy(users[client_index].username, buf); } else { for (int i = 0; i < MAX_CONNECTIONS; i++) { if (users[client_index].sock_fd != -1 && client_index != i) { int num_written = write(users[i].sock_fd, buf, strlen(buf)); if (num_written != strlen(buf)) { printf("Error"); return -1; } } } } if (num_read == 0 || write(fd, buf, strlen(buf)) != strlen(buf)) { users[client_index].sock_fd = -1; return fd; } return 0; }
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63c648c25f004bf4898cff72
2023-03-31T20:34:36.468Z
Question from Code
v2
did i correctly change the code to broadcast to all connected clients?
#ifndef PORT #define PORT 30000 #endif #define MAX_BACKLOG 5 #define MAX_CONNECTIONS 12 #define BUF_SIZE 128 int read_from(int client_index, struct sockname *users) { int fd = users[client_index].sock_fd; char buf[BUF_SIZE + 1]; int num_read = read(fd, &buf, BUF_SIZE); buf[num_read] = '\0'; if (users[client_index].username == NULL) { users[client_index].username = malloc(sizeof(char) * (strlen(buf))); strcpy(users[client_index].username, buf); } else { int num_written = write(users[client_index].sock_fd, buf, strlen(buf)); if (num_written != strlen(buf)) { printf("Error"); return -1; } } for (int i = 0; i < MAX_CONNECTIONS; i++) { if (users[client_index].sock_fd != -1 && client_index != i) { int num_written = write(users[i].sock_fd, buf, strlen(buf)); if (num_written != strlen(buf)) { printf("Error"); return -1; } } } if (num_read == 0 || write(fd, buf, strlen(buf)) != strlen(buf)) { users[client_index].sock_fd = -1; return fd; } return 0; }
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63c648c25f004bf4898cff72
2023-03-31T20:37:51.298Z
Question from Code
v2
did i correctly change the code to broadcast to all connected clients?
#ifndef PORT #define PORT 30000 #endif #define MAX_BACKLOG 5 #define MAX_CONNECTIONS 12 #define BUF_SIZE 128 int read_from(int client_index, struct sockname *users) { int fd = users[client_index].sock_fd; char buf[BUF_SIZE + 1]; int num_read = read(fd, &buf, BUF_SIZE); buf[num_read] = '\0'; if (users[client_index].username == NULL) { users[client_index].username = malloc(sizeof(char) * (strlen(buf))); strcpy(users[client_index].username, buf); } else { for (int i = 0; i < MAX_CONNECTIONS; i++) { if (users[i].sock_fd != -1 && client_index != i) { int num_written = write(users[i].sock_fd, buf, strlen(buf)); if (num_written != strlen(buf)) { printf("Error"); return -1; } } } } if (num_read == 0 || write(fd, buf, strlen(buf)) != strlen(buf)) { users[client_index].sock_fd = -1; return fd; } return 0; }
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63c648c25f004bf4898cff72
2023-03-31T20:42:56.942Z
Question from Code
v2
did i correctly change the code to broadcast to all connected clients?
#ifndef PORT #define PORT 30000 #endif #define MAX_BACKLOG 5 #define MAX_CONNECTIONS 12 #define BUF_SIZE 128 int read_from(int client_index, struct sockname *users) { int fd = users[client_index].sock_fd; char buf[BUF_SIZE + 1]; int num_read = read(fd, &buf, BUF_SIZE); buf[num_read] = '\0'; if (users[client_index].username == NULL) { users[client_index].username = malloc(sizeof(char) * (strlen(buf))); strcpy(users[client_index].username, buf); } else { for (int i = 0; i < MAX_CONNECTIONS; i++) { if (users[i].sock_fd != -1 && client_index != i) { int num_written = write(users[i].sock_fd, buf, BUF_SIZE); if (num_written != BUF_SIZE) { printf("Error"); return -1; } } } } if (num_read == 0 || write(fd, buf, strlen(buf)) != strlen(buf)) { users[client_index].sock_fd = -1; return fd; } return 0; }
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63c648c25f004bf4898cff72
2023-03-31T20:44:34.532Z
Help Fix Code
v2
Task 2: Change the code to broadcast to all connected clients
#ifndef PORT #define PORT 30000 #endif #define MAX_BACKLOG 5 #define MAX_CONNECTIONS 12 #define BUF_SIZE 128 int read_from(int client_index, struct sockname *users) { int fd = users[client_index].sock_fd; char buf[BUF_SIZE + 1]; /* In Lab 10, you focused on handling partial reads. For this lab, you do * not need handle partial reads. Because of that, this server program * does not check for "\r\n" when it reads from the client. */ int num_read = read(fd, &buf, BUF_SIZE); buf[num_read] = '\0'; if (users[client_index].username == NULL){ users[client_index].username = malloc(sizeof(char) * (strlen(buf))); strcpy(users[client_index].username, buf); }else{ for (int i = 0; i < MAX_CONNECTIONS; i++){ if (users[i].sock_fd != -1 && client_index != i){ int num_written = write(users[i].sock_fd, buf, strlen(buf)); if (num_written != strlen(buf)){ printf("Error"); return -1; } } } } if (num_read == 0 || write(fd, buf, strlen(buf)) != strlen(buf)) { users[client_index].sock_fd = -1; return fd; } return 0; }
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63c648c25f004bf4898cff72
2023-03-31T20:47:08.288Z
Question from Code
v2
Task 1: There are now two different types of input that we could receive: a username, or a message. If we have not yet received the username, then we should copy buf to username. Otherwise, the input will be a message to write to the socket.
#ifndef PORT #define PORT 30000 #endif #define MAX_BACKLOG 5 #define MAX_CONNECTIONS 12 #define BUF_SIZE 128 int read_from(int client_index, struct sockname *users) { int fd = users[client_index].sock_fd; char buf[BUF_SIZE + 1]; int num_read = read(fd, &buf, BUF_SIZE); buf[num_read] = '\0'; if (users[client_index].username == NULL) { users[client_index].username = malloc(sizeof(char) * (strlen(buf))); strcpy(users[client_index].username, buf); } else { int num_written = write(users[client_index].sock_fd, buf, strlen(buf)); if (num_written != strlen(buf)) { printf("Error"); return -1; } } if (num_read == 0 || write(fd, buf, strlen(buf)) != strlen(buf)) { users[client_index].sock_fd = -1; return fd; } return 0; }
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63c648c25f004bf4898cff72
2023-03-31T20:48:13.935Z
Question from Code
v2
Task 2: Change the code to broadcast to all connected clients
#ifndef PORT #define PORT 30000 #endif #define MAX_BACKLOG 5 #define MAX_CONNECTIONS 12 #define BUF_SIZE 128 int read_from(int client_index, struct sockname *users) { int fd = users[client_index].sock_fd; char buf[BUF_SIZE + 1]; int num_read = read(fd, &buf, BUF_SIZE); buf[num_read] = '\0'; if (users[client_index].username == NULL) { users[client_index].username = malloc(sizeof(char) * (strlen(buf))); strcpy(users[client_index].username, buf); } else { int num_written = write(users[client_index].sock_fd, buf, strlen(buf)); if (num_written != strlen(buf)) { printf("Error"); return -1; } } for (int i = 0; i < MAX_CONNECTIONS; i++) { if (users[i].sock_fd != -1 && client_index != i) { int num_written = write(users[i].sock_fd, buf, strlen(buf)); if (num_written != strlen(buf)) { printf("Error"); return -1; } } } if (num_read == 0 || write(fd, buf, strlen(buf)) != strlen(buf)) { users[client_index].sock_fd = -1; return fd; } return 0; }
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63c648c25f004bf4898cff72
2023-03-31T20:49:51.749Z
Question from Code
v2
Task 2: Change the code to broadcast to all connected clients
#ifndef PORT #define PORT 30000 #endif #define MAX_BACKLOG 5 #define MAX_CONNECTIONS 12 #define BUF_SIZE 128 int read_from(int client_index, struct sockname *users) { int fd = users[client_index].sock_fd; char buf[BUF_SIZE + 1]; int num_read = read(fd, &buf, BUF_SIZE); buf[num_read] = '\0'; if (users[client_index].username == NULL) { users[client_index].username = malloc(sizeof(char) * (strlen(buf))); strcpy(users[client_index].username, buf); } else { int num_written = write(users[client_index].sock_fd, buf, strlen(buf)); if (num_written != strlen(buf)) { printf("Error"); return -1; } } for (int i = 0; i < MAX_CONNECTIONS; i++) { if (users[i].sock_fd != -1) { int num_written = write(users[i].sock_fd, buf, strlen(buf)); if (num_written != strlen(buf)) { printf("Error"); return -1; } } } if (num_read == 0 || write(fd, buf, strlen(buf)) != strlen(buf)) { users[client_index].sock_fd = -1; return fd; } return 0; }
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63c648c25f004bf4898cff72
2023-03-31T20:51:55.670Z
Explain Code
v2
null
#ifndef PORT #define PORT 30000 #endif #define MAX_BACKLOG 5 #define MAX_CONNECTIONS 12 #define BUF_SIZE 128 for (int i = 0; i < MAX_CONNECTIONS; i++) { if (users[i].sock_fd != -1) { int num_written = write(users[i].sock_fd, buf, strlen(buf)); if (num_written != strlen(buf)) { printf("Error"); return -1; } } }
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63c648c25f004bf4898cff72
2023-03-31T20:55:09.522Z
Help Fix Code
v2
Change the code to broadcast to all connected clients
#ifndef PORT #define PORT 30000 #endif #define MAX_BACKLOG 5 #define MAX_CONNECTIONS 12 #define BUF_SIZE 128 int read_from(int client_index, struct sockname *users) { int fd = users[client_index].sock_fd; char buf[BUF_SIZE + 1]; /* In Lab 10, you focused on handling partial reads. For this lab, you do * not need handle partial reads. Because of that, this server program * does not check for "\r\n" when it reads from the client. */ int num_read = read(fd, &buf, BUF_SIZE); buf[num_read] = '\0'; if (users[client_index].username == NULL){ users[client_index].username = malloc(sizeof(char) * (strlen(buf))); strcpy(users[client_index].username, buf); }else{ int num_written = write(users[client_index].sock_fd, buf, strlen(buf)); if (num_written != strlen(buf)){ printf("Error"); return -1; } } if (num_read == 0 || write(fd, buf, strlen(buf)) != strlen(buf)) { users[client_index].sock_fd = -1; return fd; } return 0; }
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63c648c25f004bf4898cff72
2023-03-31T20:57:51.288Z
Question from Code
v2
Task 2: Change the code to broadcast to all connected clients */
#ifndef PORT #define PORT 30000 #endif #define MAX_BACKLOG 5 #define MAX_CONNECTIONS 12 #define BUF_SIZE 128 int read_from(int client_index, struct sockname *users) { int fd = users[client_index].sock_fd; char buf[BUF_SIZE + 1]; int num_read = read(fd, &buf, BUF_SIZE); buf[num_read] = '\0'; if (users[client_index].username == NULL) { users[client_index].username = malloc(sizeof(char) * (strlen(buf))); strcpy(users[client_index].username, buf); } else { int num_written = write(users[client_index].sock_fd, buf, strlen(buf)); if (num_written != strlen(buf)) { printf("Error"); return -1; } } if (num_read == 0 || write(fd, buf, strlen(buf)) != strlen(buf)) { if (broadcast(client_index, users, buf, strlen(buf)) == -1) { return -1; } users[client_index].sock_fd = -1; return fd; } return 0; }
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63c648c25f004bf4898cff72
2023-03-31T21:00:44.952Z
Question from Code
v2
Change the read_from function so that it broadcasts any message received to all connected clients.
#ifndef PORT #define PORT 30000 #endif #define MAX_BACKLOG 5 #define MAX_CONNECTIONS 12 #define BUF_SIZE 128 int read_from(int client_index, struct sockname *users) { int fd = users[client_index].sock_fd; char buf[BUF_SIZE + 1]; int num_read = read(fd, &buf, BUF_SIZE); buf[num_read] = '\0'; if (users[client_index].username == NULL) { users[client_index].username = malloc(sizeof(char) * (strlen(buf))); strcpy(users[client_index].username, buf); } else { int num_written = write(users[client_index].sock_fd, buf, strlen(buf)); if (num_written != strlen(buf)) { printf("Error"); return -1; } } if (num_read == 0 || write(fd, buf, strlen(buf)) != strlen(buf)) { if (broadcast(client_index, users, buf, strlen(buf)) == -1) { return -1; } users[client_index].sock_fd = -1; return fd; } return 0; }
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63c648c25f004bf4898cff72
2023-03-31T21:01:12.864Z
Help Fix Code
v2
Change the read_from function so that it broadcasts any message received to all connected clients.
#ifndef PORT #define PORT 30000 #endif #define MAX_BACKLOG 5 #define MAX_CONNECTIONS 12 #define BUF_SIZE 128 int read_from(int client_index, struct sockname *users) { int fd = users[client_index].sock_fd; char buf[BUF_SIZE + 1]; /* In Lab 10, you focused on handling partial reads. For this lab, you do * not need handle partial reads. Because of that, this server program * does not check for "\r\n" when it reads from the client. */ int num_read = read(fd, &buf, BUF_SIZE); buf[num_read] = '\0'; if (users[client_index].username == NULL){ users[client_index].username = malloc(sizeof(char) * (strlen(buf))); strcpy(users[client_index].username, buf); }else{ int num_written = write(users[client_index].sock_fd, buf, strlen(buf)); if (num_written != strlen(buf)){ printf("Error"); return -1; } } if (num_read == 0 || write(fd, buf, strlen(buf)) != strlen(buf)) { if (broadcast(client_index, users, buf, strlen(buf)) == -1){ return -1; } users[client_index].sock_fd = -1; return fd; } return 0; }
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63c648c25f004bf4898cff72
2023-03-31T21:05:21.335Z
Question from Code
v2
Task 2: Change the code to broadcast to all connected clients
#ifndef PORT #define PORT 30000 #endif #define MAX_BACKLOG 5 #define MAX_CONNECTIONS 12 #define BUF_SIZE 128 int read_from(int client_index, struct sockname *users) { int fd = users[client_index].sock_fd; char buf[BUF_SIZE + 1]; int num_read = read(fd, &buf, BUF_SIZE); buf[num_read] = '\0'; if (users[client_index].username == NULL) { users[client_index].username = malloc(sizeof(char) * (strlen(buf))); strcpy(users[client_index].username, buf); } else { int num_written = write(users[client_index].sock_fd, buf, strlen(buf)); if (num_written != strlen(buf)) { printf("Error"); return -1; } for (int i = 0; i < MAX_CONNECTIONS; i++) { if (users[i].sock_fd != -1) { write(users[i].sock_fd, buf, strlen(buf)); } } } if (num_read == 0 || write(fd, buf, strlen(buf)) != strlen(buf)) { users[client_index].sock_fd = -1; return fd; } return 0; }
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63c648c25f004bf4898cff72
2023-03-31T21:06:56.054Z
Question from Code
v2
did I correctly Change the code to broadcast to all connected clients
#ifndef PORT #define PORT 30000 #endif #define MAX_BACKLOG 5 #define MAX_CONNECTIONS 12 #define BUF_SIZE 128 int read_from(int client_index, struct sockname *users) { int fd = users[client_index].sock_fd; char buf[BUF_SIZE + 1]; int num_read = read(fd, &buf, BUF_SIZE); buf[num_read] = '\0'; if (users[client_index].username == NULL) { users[client_index].username = malloc(sizeof(char) * (strlen(buf))); strcpy(users[client_index].username, buf); } else { int num_written = write(users[client_index].sock_fd, buf, strlen(buf)); if (num_written != strlen(buf)) { printf("Error"); return -1; } for (int i = 0; i < MAX_CONNECTIONS; i++) { if (users[i].sock_fd != -1 && client_index != i) { write(users[i].sock_fd, buf, strlen(buf)); } } } if (num_read == 0 || write(fd, buf, strlen(buf)) != strlen(buf)) { users[client_index].sock_fd = -1; return fd; } return 0; }
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63c648c25f004bf4898cff72
2023-03-31T21:10:58.967Z
Question from Code
v2
did I correctly Change the code to broadcast to all connected clients
#ifndef PORT #define PORT 30000 #endif #define MAX_BACKLOG 5 #define MAX_CONNECTIONS 12 #define BUF_SIZE 128 int read_from(int client_index, struct sockname *users) { int fd = users[client_index].sock_fd; char buf[BUF_SIZE + 1]; int num_read = read(fd, &buf, BUF_SIZE); buf[num_read] = '\0'; if (users[client_index].username == NULL) { users[client_index].username = malloc(sizeof(char) * (strlen(buf))); strcpy(users[client_index].username, buf); } else { if (write(users[client_index].sock_fd, buf, strlen(buf)) != strlen(buf)) { perror("client: write"); close(sock_fd); exit(1); } for (int i = 0; i < MAX_CONNECTIONS; i++) { if (users[i].sock_fd != -1 && client_index != i) { if (write(users[i].sock_fd, buf, strlen(buf)) != strlen(buf)) { perror("client: write"); close(sock_fd); exit(1); } } } } if (num_read == 0 || write(fd, buf, strlen(buf)) != strlen(buf)) { users[client_index].sock_fd = -1; return fd; } return 0; }
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63c648c25f004bf4898cff72
2023-03-31T21:28:34.475Z
Question from Code
v2
how to Monitor stdin and the socket using select to avoid blocking on either one.
#ifndef PORT #define PORT 30000 #endif #define MAX_BACKLOG 5 #define MAX_CONNECTIONS 12 #define BUF_SIZE 128 while (1) { num_read = read(STDIN_FILENO, buf, BUF_SIZE); if (num_read == 0) { break; } buf[num_read] = '\0'; if (write(sock_fd, buf, num_read) != num_read) { perror("client: write"); close(sock_fd); exit(1); } num_read = read(sock_fd, buf, sizeof(buf) - 1); if (num_read == 0) { break; } buf[num_read] = '\0'; printf("[Server] %s", buf); }
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63c648c25f004bf4898cff72
2023-03-31T21:29:52.976Z
Help Fix Code
v2
Monitor stdin and the socket using select to avoid blocking on either one.
#ifndef PORT #define PORT 30000 #endif #define MAX_BACKLOG 5 #define MAX_CONNECTIONS 12 #define BUF_SIZE 128 while (1) { num_read = read(STDIN_FILENO, buf, BUF_SIZE); if (num_read == 0) { break; } buf[num_read] = '\0'; /* * We should really send "\r\n" too, so the server can identify partial * reads, but you are not required to handle partial reads in this lab. */ if (write(sock_fd, buf, num_read) != num_read) { perror("client: write"); close(sock_fd); exit(1); } num_read = read(sock_fd, buf, sizeof(buf) - 1); if (num_read == 0) { break; } buf[num_read] = '\0'; printf("[Server] %s", buf); }
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63c648c25f004bf4898cff72
2023-03-31T21:47:01.464Z
Help Fix Code
v2
Your task is to update the client so it monitors just two file descriptors: the socket with the server and stdin. Whenever a message is received on either, your program should read it and pass it to the correct output stream.
#ifndef PORT #define PORT 30000 #endif #define MAX_BACKLOG 5 #define MAX_CONNECTIONS 12 #define BUF_SIZE 128 while (1) { num_read = read(STDIN_FILENO, buf, BUF_SIZE); if (num_read == 0) { break; } buf[num_read] = '\0'; /* * We should really send "\r\n" too, so the server can identify partial * reads, but you are not required to handle partial reads in this lab. */ if (write(sock_fd, buf, num_read) != num_read) { perror("client: write"); close(sock_fd); exit(1); } num_read = read(sock_fd, buf, sizeof(buf) - 1); if (num_read == 0) { break; } buf[num_read] = '\0'; printf("[Server] %s", buf); }
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63c648c25f004bf4898cff72
2023-03-31T21:48:44.810Z
Help Fix Code
v2
Your task is to update the client so it monitors just two file descriptors: the socket with the server and stdin. Whenever a message is received on either, your program should read it and pass it to the correct output stream.
while (1) { num_read = read(STDIN_FILENO, buf, BUF_SIZE); if (num_read == 0) { break; } buf[num_read] = '\0'; /* * We should really send "\r\n" too, so the server can identify partial * reads, but you are not required to handle partial reads in this lab. */ if (write(sock_fd, buf, num_read) != num_read) { perror("client: write"); close(sock_fd); exit(1); } num_read = read(sock_fd, buf, sizeof(buf) - 1); if (num_read == 0) { break; } buf[num_read] = '\0'; printf("[Server] %s", buf); }
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63c648c25f004bf4898cff72
2023-03-31T22:09:22.805Z
Help Fix Code
v2
Monitor stdin and the socket using select to avoid blocking on either one.
while (1) { num_read = read(STDIN_FILENO, buf, BUF_SIZE); if (num_read == 0) { break; } buf[num_read] = '\0'; /* * We should really send "\r\n" too, so the server can identify partial * reads, but you are not required to handle partial reads in this lab. */ if (write(sock_fd, buf, num_read) != num_read) { perror("client: write"); close(sock_fd); exit(1); } num_read = read(sock_fd, buf, sizeof(buf) - 1); if (num_read == 0) { break; } buf[num_read] = '\0'; printf("[Server] %s", buf); }
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63c648c25f004bf4898cff72
2023-03-31T22:12:26.200Z
Help Fix Code
v2
Monitor stdin and the socket using select to avoid blocking on either one. Update the client so it monitors just two file descriptors: the socket with the server and stdin. Whenever a message is received on either, your program should read it and pass it to the correct output stream.
while (1) { num_read = read(STDIN_FILENO, buf, BUF_SIZE); if (num_read == 0) { break; } buf[num_read] = '\0'; /* * We should really send "\r\n" too, so the server can identify partial * reads, but you are not required to handle partial reads in this lab. */ if (write(sock_fd, buf, num_read) != num_read) { perror("client: write"); close(sock_fd); exit(1); } num_read = read(sock_fd, buf, sizeof(buf) - 1); if (num_read == 0) { break; } buf[num_read] = '\0'; printf("[Server] %s", buf); }
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63c648c25f004bf4898cff72
2023-03-31T22:14:39.058Z
Question from Code
v2
Monitor stdin and the socket using select to avoid blocking on either one. Update the client so it monitors just two file descriptors: the socket with the server and stdin. Whenever a message is received on either, your program should read it and pass it to the correct output stream.
while (1) { num_read = read(STDIN_FILENO, buf, BUF_SIZE); if (num_read == 0) { break; } buf[num_read] = '\0'; if (write(sock_fd, buf, num_read) != num_read) { perror("client: write"); close(sock_fd); exit(1); } num_read = read(sock_fd, buf, sizeof(buf) - 1); if (num_read == 0) { break; } buf[num_read] = '\0'; printf("[Server] %s", buf); }
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63c648c25f004bf4898cff72
2023-04-04T03:43:05.315Z
General Question
v2
Consider the sh script shifter.sh: echo I live at $1 $2 $3. shift echo Now, I live at $0 $1 $2. Suppose I run the script as follows: sh shifter.sh 100 University Ave What does it output?
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63c648c25f004bf4898cff72
2023-04-04T03:51:10.425Z
General Question
v2
In a shell program, what variable has the number of arguments that were supplied to the program?
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63c648c25f004bf4898cff72
2023-04-04T04:02:08.841Z
General Question
v2
Consider the follow code: subject=CSC Using subject, write a command to output: Last week of CSC209
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63c648c25f004bf4898cff72
2023-04-04T04:08:08.712Z
Question from Code
v2
Using subject, write a command to output: Last week of CSC209 for shell programming
subject = CSC
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63c648c55f004bf4898cff90
2023-02-10T14:30:42.497Z
General Question
v1
How to allocate memory in heap?
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63c648c55f004bf4898cff90
2023-02-11T01:44:45.659Z
Help Fix Code
v1
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struct pixel read_pixel_array(FILE *image, int pixel_array_offset, int width, int height) { //allocate rows struct pixel** rows = malloc(height * sizeof(struct pixel*)); if (rows == NULL){ exit(1); } //alocate each row for (int i=0; i<height; i++) { rows[i] = malloc(width * sizeof(struct pixel)); if (rows[i] == NULL){ exit(1); } } //read into memory fseek(image, pixel_array_offset, SEEK_SET); for (int i=0; i<height; i++) { for (int j=0; j<width; j++) { unsigned char r; unsigned char g; unsigned char b; fread(&b, sizeof(char), 1, image); fread(&g, sizeof(char), 1, image); fread(&r, sizeof(char), 1, image); struct pixel pix; pix.blue = b; pix.green = g; pix.red = r; rows[i][j] = pix; } } return rows; }
return an array of arrays of pixels
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63c648c55f004bf4898cff90
2023-02-14T17:43:10.202Z
Help Fix Code
v1
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if (((*user_ptr_add)[0]) == NULL){ }
check if the first element of the array pointed to by user_ptr_add is empty
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63c648c55f004bf4898cff90
2023-02-14T18:39:03.174Z
Help Fix Code
v1
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user_pt->name = malloc(sizeof(char)*32);
Allocate memory for the name of struct pointed to by user_pt in the heap
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63c648c55f004bf4898cff90
2023-02-14T18:40:14.450Z
Help Fix Code
v1
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user_pt->name = malloc(sizeof(char)*32);
allocate space in heap for the name field of the struct pointed to by user_pt
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63c648c55f004bf4898cff90
2023-02-14T19:08:19.311Z
Explain Code
v1
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typedef struct user { char name[MAX_NAME]; char profile_pic[MAX_NAME]; // This is a *filename*, not the file contents. struct post *first_post; struct user *friends[MAX_FRIENDS]; struct user *next; } User;
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63c648c55f004bf4898cff90
2023-02-14T19:09:49.534Z
Question from Code
v1
Why is User on line 7 capitalised?
typedef struct user { char name[MAX_NAME]; char profile_pic[MAX_NAME]; // This is a *filename*, not the file contents. struct post *first_post; struct user *friends[MAX_FRIENDS]; struct user *next; } User;
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63c648c55f004bf4898cff90
2023-02-14T19:12:07.302Z
Question from Code
v1
Why do we use typedef here?
typedef struct user { char name[MAX_NAME]; char profile_pic[MAX_NAME]; // This is a *filename*, not the file contents. struct post *first_post; struct user *friends[MAX_FRIENDS]; struct user *next; } User;
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63c648c55f004bf4898cff90
2023-02-14T23:55:08.871Z
General Question
v1
how to check if an array element is empty?
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63c648c55f004bf4898cff90
2023-02-15T02:04:39.151Z
Help Write Code
v1
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Read file line by line
63c648c55f004bf4898cff90
2023-02-15T02:35:01.101Z
Help Write Code
v1
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convert time_t to string
63c648c55f004bf4898cff90
2023-02-15T05:47:51.054Z
General Question
v1
How to use valgrind
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63c648c55f004bf4898cff90
2023-02-15T05:54:54.855Z
General Question
v1
can junk values from freed heap memory interfere with values of memory allocated with malloc?
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63c648c55f004bf4898cff90
2023-03-03T18:48:36.097Z
General Question
v1
What header do I need to use the wait function?
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63c648c55f004bf4898cff90
2023-03-03T18:49:06.724Z
General Question
v1
How do I use wait
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63c648c55f004bf4898cff90
2023-03-10T23:20:28.105Z
Help Fix Code
v2
write 10 bytes of each password and user_id to pipe
for (int i=0; i<MAXPASSWORD; i++){ if (write(fd[1], user_id+i, 1) == -1){ perror("write"); exit(1); } } for (int i=0; i<MAXPASSWORD; i++){ if (write(fd[1], password+i, 1) == -1){ perror("write"); exit(1); } }
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63c648c55f004bf4898cff90
2023-03-10T23:21:41.793Z
General Question
v2
How do I write to a pipe twice?
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63c648c55f004bf4898cff90
2023-03-14T17:08:27.379Z
General Question
v2
How do I split a string up
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63c648c55f004bf4898cff90
2023-03-15T13:05:56.149Z
Explain Code
v2
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int (*complex(int index))(char *s, int l);
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63c648c65f004bf4898cff95
2023-01-17T15:10:22.245Z
General Question
v1
what is a seg fault??
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63c648c65f004bf4898cff95
2023-01-17T15:31:25.689Z
Question from Code
v1
what object does this line of code create?
char *result[2];
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63c648c65f004bf4898cff95
2023-01-17T15:41:16.761Z
Question from Code
v1
what does this code output
int x; printf('\d', x);
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63c648c65f004bf4898cff95
2023-01-17T15:41:52.306Z
Question from Code
v1
what does this code output
int x; printf("\d", x);
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63c648c65f004bf4898cff95
2023-01-17T15:48:38.929Z
Question from Code
v1
what is the type of the variable y
char *result[2]; x = result[0]; // some hidden code result[0] = "read only"; y = x[0];
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63c648c65f004bf4898cff95
2023-01-25T06:05:49.310Z
Question from Code
v1
why does this code produce a segmentation fault?
void fib(int **sequence, int num_elements) { *sequence = malloc(sizeof(int) * num_elements); *sequence[0] = 0; if (num_elements >= 1) { *sequence[1] = 1; for (int i = 2; i < num_elements; i++) { *sequence[i] = *sequence[i - 2] + *sequence[i - 1]; } } } int main(int argc, char **argv) { /* do not change this main function */ int count = strtol(argv[1], NULL, 10); int *fib_sequence; fib(&fib_sequence, count); for (int i = 0; i < count; i++) { printf("%d ", fib_sequence[i]); } free(fib_sequence); return 0; }
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63c648c65f004bf4898cff95
2023-01-25T06:15:31.101Z
Question from Code
v1
the code results in a segmentation fault, why did it take place?
void fib(int **sequence, int num_elements) { *sequence = malloc(sizeof(int) * num_elements); *sequence[0] = 0; if (num_elements >= 1) { *sequence[1] = 1; for (int i = 2; i < num_elements; i++) { *sequence[i] = *sequence[i - 2] + *sequence[i - 1]; } } } int main(int argc, char **argv) { /* do not change this main function */ int count = strtol(argv[1], NULL, 10); int *fib_sequence; fib(&fib_sequence, count); for (int i = 0; i < count; i++) { printf("%d ", fib_sequence[i]); } free(fib_sequence); return 0; }
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63c648c65f004bf4898cff95
2023-01-25T06:19:26.356Z
Help Fix Code
v1
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void fib(int **sequence, int n) { *sequence = malloc(sizeof(int) * n); *sequence[0] = 0; if (n >= 1) { *sequence[1] = 1; for (int i = 2; i < n; i++) { *sequence[i] = *sequence[i - 2] + *sequence[i - 1]; } } } int main(int argc, char **argv) { /* do not change this main function */ int count = strtol(argv[1], NULL, 10); int *fib_sequence; fib(&fib_sequence, count); for (int i = 0; i < count; i++) { printf("%d ", fib_sequence[i]); } free(fib_sequence); return 0; }
code takes in an int n, and generates and prints out the first n elements of the Fibonacci sequence.
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