i'm quite familiar with Java, not so in C.

In Java, if i have a method that does something and returns a String, it would look like:

private String doSomething(...) {
    String s;
    // do something;
    return s;
}

The syntactic equivalent in C would not work and is plain wrong:

char* doSomething(...) {
    char s[100];
    // do something;
    return s;
}

of course i can do:

char* doSomething(...) {
    char *s;
    s = malloc(100 * sizeof(char));
    // do something;
    return s;
}

which would work (i think!) but i seldom see codes doing this way (is it because it's unnecessarily filling the heap?)

most commonly, i see:

bool doSomething(char *s) {
    // do something that copies chars to s
    return true;
}

And the calling statements would be:

char s[100];
doSomething(s);

What if I do not know the size of the char array until inside the function itself? i.e. I would not be able to declare the char array outside the function and then pass it in.

What would be the correct way to deal with such a scenario?

c string dynamic-allocation
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