Question

I have this code behaving weirdly:

int main() {

    string a = "TRY";
    string b = "THIS";

    a += b[0] + '!';      //This outputs "TRYu"?
    //a = a + b[0] + '!'; //This outputs "TRYT!" as expected.

    cout << a;

}

Shouldn’t the above two statements be the same?

Answer 1

No. Your first example is not equal to

a = a + b[0] + '!'

But rather to

a = a + ( b[0] + '!' )

You know that a char is a numeric value. Since both b[0] and '!' are chars, b[0] + '!' will NOT give you a concatenation but an addition (b[0] + 33, basically). Then you will try to append the ASCII character of code b[0] + 33 into your string. Since b[0] is 'T' (ASCII 84), you end up with the character of ASCII code 117 : 'u'.

You will have to replace '!' by std::string("!") to fix the code and make a concatenation.