How can I ignore certain strings in my string centring function?

Question

N.B: Directly connected to a problem I had a few years ago, but I\'d like to resolve the first issue there which wasn\'t otherwise part of the question, so please don\'t fla

Answer 1

So, what you are really trying to do is count the instances of $N in your string, where N is a decimal digit. To do this, just look in the string for instances of $ using std::string::find, and then check the next character to see if it is a digit.

std::string::size_type pos = 0;
while ((pos = input.find('$', pos)) != std::string::npos) {
    if (pos + 1 == input.size()) {
        break;  //  The last character of the string is a '$'
    }
    if (std::isdigit(input[pos + 1])) {
        width += 2;
    }
    ++pos;  //  Start next search from the next char
}

In order to use std::isdigit, you need to first:

#include <cctype>