index of char array is returning ascii values instead of actual char?

Question

I am trying to recreate a simple version of the string class in C++. I am currently having trouble with some functions like the substring() function.

My private member data includes this:

    char* chars;
    unsigned int size;

And my function definition is here:

FunString FunString::substring(unsigned int a, unsigned int b) const {
    //return substring from index a to b
    //check if substring is in correct bounds
    FunString temp;
    for (unsigned int i = a; i < b; i++) {
        temp.chars[i] = chars[i];
    }
    return temp;
}

I am trying to just recreate the classic substring function but when I try this:

int main() {
    FunString s = "Hellooooo";
    FunString b;
    b = s.substring(0,4);
    cout << b;
    return 0;
}

It outputs this:

Hell└

Any idea what's going on here?

Answer 1

The problem you have is that you builded temp string properly, but didn't add '\0' at the end. So then printing string you get your string + some things that lay after it in the memory.

FunString FunString::substring(unsigned int a, unsigned int b) const {
    FunString temp;
    for (unsigned int i = a; i < b; i++) {
        temp.chars[i] = chars[i];
    }
    temp.chars[b] = '\0'; // you should add this line 
    return temp;
}