#include <iostream>
#include <iomanip>
#include <map>
#include <string>
#include <cstdlib>
using namespace std;

using fraction = pair<int,int>;

ostream& operator<<(ostream&, const fraction&);
ostream& operator<<(ostream&, const pair<double,fraction>&);
ostream& operator<<(ostream&, const multimap<double,fraction>&);


int main()
{
    multimap<double,fraction> fractions;

    // insert 7 elements into the multimap
    fractions.insert(pair<double,fraction>(.75,fraction(3,4)));
    fractions.insert(pair<double,fraction>(.75,fraction{6,8}));
    fraction neg_3_4{-3,-4};
    fractions.insert(pair<double,fraction>(.75,neg_3_4));

    fraction temp_fraction{1,2};
    pair<double,fraction> temp_double_fraction;
    temp_double_fraction = {.5,temp_fraction};

    fractions.insert(temp_double_fraction);
    fractions.insert({.5,{2,4}});
    fractions.insert({.333,{1,3}});
    fractions.insert({.25,{1,4}});
    fractions.insert({.5,{1,2}});
    cout << fractions << endl << endl;

    // fractions[.4] = fraction(2,5);  // Error: no index operator
    multimap<double,fraction>::const_iterator cIt;
    cIt = fractions.find(.333);
    cout << "fractions.find(.333): " << *cIt << endl;
    cout << "fractions.find(.75): " <<*fractions.find(.75) << endl;
    cIt = fractions.find(.55);
    cout << "fractions.find(.55): " <<*cIt << endl;
    if (cIt == fractions.end())
        cout << "Can't find .55" << endl << endl;

    cout << "fractions.count(.5)=" << fractions.count(.5) << endl;
    cout << "fractions.count(.6)=" << fractions.count(.6) << endl << endl;

    cout << "Elements with key = .5" << endl;
    for (cIt = fractions.lower_bound(.5); cIt != fractions.upper_bound(.5); ++cIt)
        cout << *cIt << endl;
}

ostream& operator<<(ostream& out, const fraction& obj)
{
    out << obj.first << '/' << obj.second;
    return out;
}

ostream& operator<<(ostream& out, const pair<double,fraction>& obj)
{
  out << "first: " << obj.first << "  second: " << obj.second;
  return out;
}
ostream& operator<<(ostream& out, const multimap<double,fraction>& obj)
{
  for (auto it = obj.cbegin(); it != obj.cend(); ++it)
      out << "key: " << it->first << "  value: " << it->second << endl;
  return out;
}