segmentation fault when returning string from function

I was wondering what this code should print. I wanted to check whether it prints we can, can we or we can, but instead i got segmentation fault.

Here is the code:

char* mysubstr() {
    char* x = "Yes we can, can we";
    char* y = "we can";
    char* tmp = x;
    
    while(*tmp) {
        if (*tmp == *y)
            return *tmp;
        tmp++;
    }
    return x;
}


void main() {
    printf("%s", mysubstr());
}

I think the wrong part is the return *tmp;, but why? What’s wrong with that?

>Solution :

Your compiler basically already told you what is wrong:

return makes pointer from integer without a cast

This is because you define a function returning a char * but you return a char.

With char *tmp = x; you define a pointer and in your return statement you dereference it.
Hence you return (char*)'w'

If you use that return value for printf value 'w' is taken an address which causes your crash.

You should just do return tmp;

This is not the only issue in your code.
Your function name indicates you want to make some substring function.
Bur your code returns immediately it found a match of first letter in second string. You don’t verify if the other character also are same.