String

#include <iostream>
#include<string>


char pom (char c)
{
    c+=1;
    return c;
}

void funkcija(std::string &s, char f(char))
{
    std::string novi="";
    for(int i=0; i<s.size(); i++)
        novi += f(s[i]);
    s = novi;

}



int main()
{

    std::string s = "abcdfg";
    funkcija(s, pom);
    std::cout<<s;

    return 0;
}