Altering the contents of an array?

Thanks for the help, I will attempt to swap gets() for fgets(). I have done some reading and understand that fgets() is a safer method, but I haven't gotten it to work yet. When I replace gets() with fgets(), my execv() call does not work.

I am attempting to alter the contents of an array of characters in order to alter the PATH of my shell program. I assign the contents of my temporary newPath at index i to the original path, and then I print the contents of path at i to make sure the array elements have changed. However, when I call getPATH the array that is printed is my original character array "/bin/". How do I alter the contents and ensure they stay that way?

char path[50] = "/bin/";    if (strcmp(str, "getPATH") == 0){ //getPATH function       printf("%s\n", path);  }    else if (strcmp(str, "setPATH") == 0){ //setPATH function      printf("Set PATH > ");      char newPath[50];      gets(newPath);      printf("%s\n", newPath);      for (int i = 0; i < strlen(newPath); i++){          path[i] = newPath[i];          printf("%c\n", path[i]);      }  }  

Output:

> getPATH  /bin/  > setPATH  Set PATH > newpath  newpath  n  e  w  p  a  t  h  > getPATH  /bin/  >   

Full code:

#include <stdio.h>  #include <unistd.h>  #include <sys/types.h>  #include <sys/wait.h>  #include <string.h>  #include <stdlib.h>    int main(void){    while (1){      pid_t pid;      char path[50] = "/bin/";      char str[50];      printf("> ");      //fgets(str, 50, stdin); //Could never get fgets to work, dunno why      gets(str); //I know gets is worse but fgets won't work      //printf("%s\n", str); //why does c work like this      if (strcmp(str, "exit") == 0){ //exit condition        return 0;      }      else if ((pid = fork()) == 0){ //child process                  char hist[20][50];                  if (strcmp(str, "getPATH") == 0){ //getPATH function       printf("%s\n", path);         }         else if (strcmp(str, "setPATH") == 0){ //setPATH function       printf("Set PATH > ");       char newPath[50];       gets(newPath);       printf("%s\n", newPath);       strcpy(path, newPath);       printf("%s\n", path);       //for (int i = 0; i < strlen(newPath); i++){       //path[i] = newPath[i];       //printf("%c\n", path[i]);       //}         }           else if (strcmp(str, "history") == 0){         }           else {       char *token = strtok(str, " "); //tokenize input command       char *toks[20];       toks[0] = token;       int numarg = 1;       while (token != NULL){         token = strtok(NULL, " ");         toks[numarg] = token;         numarg++;       }       strcat(path, toks[0]); //concatenate command to path       //int rv = execvp(toks[0], toks);       int rv = execv(path, toks);        if (rv == -1){         printf("Command Error\n");       }         }      }      else{        wait(NULL);      }    }    return 0;  }  

https://stackoverflow.com/questions/66593488/altering-the-contents-of-an-array March 12, 2021 at 10:48AM