#include <string>
#include <cstdarg>
#include <iostream>

std::string string_replace(std::string s, char r, int countc, ...)
{
    char p;
    va_list ap;
    va_start(ap, countc);
    for(int j = 0; j < countc; ++j)
    {
        p = va_arg(ap, char);
        for(char &c : s)
        {
            if(c == p)
            {
                c = r;
            }
        }
    }
    va_end(ap);
    return s;
}

int main()
{
    std::cout << string_replace("aeiou and sometimes y", 'z', 5, 'a', 'e', 'i', 'o', 'u') << std::endl;
}