Question

I wrote the following:

#include <stdio.h>
#include <string.h>
char* getString();

char* getString(){
    char str[10];
    gets(str);
    return str;

}

int main() {

    char* s;
    s=getString();
    strcpy(s,"Hi");
    puts(s);
    return 0;
}

I know that the length of str must be less than 10, but even when I wrote just “Hi”, nothing was being printed. as far as I see it, it should be Ok. the compiler says that fgets is dangerous and should not be used.

What is the reason that nothing being printed on the screen?

Answer 1

char str[10];
// ...
return str;

This is wrong!!! Local variables are invalidated when their scope exits; thus using returned array is undefined behavior. You have to malloc a string and return it:

return strdup(str);