#include <iostream>
#include <cstddef>
#include <string>
using namespace std;

string textWrap(string str, int chars) {
string end = "n";

int charTotal = str.length();
while (charTotal>0) {
    if (str.at(chars) == ' ') {
        str.replace(chars, 1, end);
    }
    else {
        str.replace(str.rfind(' ',chars), 1, end);
    }
    charTotal -= chars;
}
return str;
}

//function call
cout << textWrap("I want to wrap this text after about 15 characters please.", 15);

std::string textWrap(string str, int location) {
    str.at(str.rfind(" ", location)) = 'n';
    return str;
}

int main(){
    std::cout << textWrap("I want to wrap this text after about 15 characters please.", 15);
}