strcpy导致线程1：信号SIGABRT

Question

I'm just doing some practice code but I can't figure out this stubborn Thread 1:

signal SIGABRT error.

int main(){
    char diet[] = "vegan";

    printf("Because of health concerns, my diet is now %s.\n", diet);

    strcpy(diet, "whatever");

    printf("Before the health concerns, my diet was %s.\n", diet);


    return 0;
}

Answer 1

strlen("whatever") > strlen("vegan") = undefined behavior.

Why do you think you need to copy the strings around. You could just do:

int main(){
    char *diet = "vegan";
    printf("Because of health concerns, my diet is now %s.\n", diet);
    diet = "whatever";
    printf("Before the health concerns, my diet was %s.\n", diet);
    return 0;
}

Answer 2

You need to allocate more memory to solve this; you cannot store 9 bytes in 6 bytes space — that causes an error.

Solution

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

char *create(const char *src) { 
   char *ret = calloc(sizeof(char*) , strlen(src) + 1);
   strcpy(ret , src);
   return ret;
}

int main(){
   char *diet = create("Vegan");
   printf("Because of health concerns, my diet is now %s.\n", diet);
   free(diet); // always free it after using it or before changing it

   diet = create("whatever");
   printf("Before the health concerns, my diet was %s.\n", diet);
   free(diet);

   return 0;
}