Question

Why I cannot initialize string with “\x”

string s = "\x"

It would be useful if I could later write:

int grade = 0;
while (cin >> grade)
    if (grade < 60)
        cout << "Your grade letter is F!";
    else {
        x = 50 - grade/10;
        s = s + static_cast<string>(x);
        cout << "Your grade letter is " << s << endl; 
    }

I prefer answer, that uses escape sequences computation for setting grade letter.

Answer 1

Because the syntax forbids it. The \x sequence in a string literal is a prefix that means “here comes the hexadecimal code for a character”, but you’re trying to omit the code part. That means it’s not possible to parse the literal and figure out which character to put in the string.

Note that this is a compile-time thing, it has to be possible to compute the sequence of characters represented by a string literal, by just looking at the literal itself.