How do I print elements of structures contained in an array - c

Question

I have created an array of structure as a global variable. I initialised the array in a function and I could print out the elements of the structure from there. My problem is that I can't print out values of the array in another function( main() in my case) other than the one I used to initialise the array. Please how can I print those values? Thank you.
#include <stdio.h>
#include <stdlib.h>
/*
*
*/
typedef struct s{
char *value;
} S;
S list[2];
void function( ){
char val1[] = "val1";
char val2[] = "val2";
S v1 = {val1};
S v2 = {val2};
list[0] = v1;
list[1] = v2;
printf("%s\n", list[1].value); //prints val2
}
int main(int argc, char** argv) {
function();
printf("%s", list[1].value); //prints nonsense
return 0;
}
What I have tried :
I modified function() to take list as an argument( function (list)) and declared list in main() instead. It didn't work.
I modified function to return list (S* function()), it didn't work.
I used an array of integers ( instead of structure i.e. int list[2], declared it as a global variable and initialised it in function()) and everything worked fine, suggesting that the problem is from how I am accessing structure, but I just can't figure it out.
I searched the internet, but couldn't get a similar problem.

Answer 1

In your function function you assign an address of a local variable to your structure. After returning from function this address is no longer valid. You could either make it static or allocated it dynamically.
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
typedef struct s
{
char *value;
} S;
S list[2];
void function( )
{
char val1[] = "val1";
char val2[] = "val2";
//Note that you are creating a copy of "val1" here which can be avoided by changing it to char *val1 = "val1";
list[0].value = malloc(strlen(val1)+1); //allocate space for val1 + NUL-terminator
strcpy(list[0].value, val1); //copy string
list[1].value = malloc(strlen(val2)+1);
strcpy(list[1].value, val2);
//You could also use the function strdup which allocates memory and duplicates the string
//list[0].value = strdup(val1);
printf("%s\n", list[1].value); //prints val2
}
int main(int argc, char** argv)
{
function();
printf("%s", list[1].value);
free(list[0].value); //Don't forget to free.
free(list[1].value);
return 0;
}