function pointer parameter

fpp.cpp

#include <iostream> /// std::cout; std::endl;

void useBigger (const std::string &s1, const std::string &s2, /// function useBigger has a parameters of two reference to const string and one pointer type that has paramters pf two const string and returns bool and returns void
                bool (*pf)(const std::string &, const std::string &))
                {
                    bool valid = pf (s1, s2); /// equivalent as lengthCompare (s1, s2);
                    std::cout << __func__ << " is called "
                              << valid <<std::endl;
                }

bool lengthCompare (const std::string &s1, const std::string &s2)
{
    if (s1.size() > s2.size())
        return true;
    else
        return false;
}

int main()
{
    useBigger ("hello", "assholes", lengthCompare); /// passes the two argument strings and one function 

    return 0;
}