Everything about pair

#include<bits/stdc++.h>
using namespace std;


bool cmp ( const pair<int,int> &p1, const pair<int, int> &p2  )
{
    if ( p1.first > p2.first ) return 1;
    if ( p1.first == p2.first ) return ( p1.second < p2.second );
    return 0;
}

int main()
{

    /// Declear a pair o integers

    pair<int,int> p;

    p = make_pair ( 2, 3 );
    cout << p.first << " " << p.second << endl; /// 2 3

    p.first++;
    cout << p.first << " " << p.second << endl; /// 3 3

    pair<int, int> p1 = { 2, 3 };
    pair<int, int> p2 = { 1, 6 };

    /// Getting minimum of 2 pairs
    p = min ( p1, p2 );
    cout << p.first << " " << p.second << endl; /// 1 6

    /// Getting maximum of 2 pairs
    p = max ( p1, p2 );
    cout << p.first << " " << p.second << endl; /// 2 3

    /// Sorting pair of integers

    vector<pair<int,int>> v;
    v.push_back ( { 1, 5 } );
    v.push_back ( { 2, 5 } );
    v.push_back ( { 7, 1 } );
    v.push_back ( { 3, 6 } );
    v.push_back ( { 3, 6 } );
    v.push_back ( { 7, 1 } );

    sort ( v.begin(), v.end() );
    for ( auto u : v ) cout << u.first << " " << u.second << endl;
    cout << endl;
    /**
    1 5
    2 5
    3 6
    3 6
    7 1
    7 1

    */

    /// Making unique pair of integers

    int Sz = unique ( v.begin(), v.end() ) - v.begin();
    cout << Sz << endl;
    for ( int i = 0; i < Sz; i++ ) cout << v[i].first << " " << v[i].second << endl;
    cout << endl;

    /**
    4
    1 5
    2 5
    3 6
    7 1

    */

    /// sorting using comparator
    v = { {2, 3}, {4, 5}, {1, 5}, {1, 6}, {6, 7}, {6, 8} };

    sort ( v.begin(), v.end(), cmp );
    for ( auto u : v ) cout << u.first << " " << u.second << endl;
    cout << endl;

    /**

    6 7
    6 8
    4 5
    2 3
    1 5
    1 6

    */


    v = { {2, 3}, {4, 5}, {1, 5}, {1, 6}, {6, 7}, {6, 8} };

    for ( int i = 0; i < v.size(); i++ ) v[i].first *= -1;
    sort ( v.begin(), v.end() );
    for ( auto u : v ) cout << (u.first*-1) << " " << u.second << endl;
    cout << endl;

    /**

    6 7
    6 8
    4 5
    2 3
    1 5
    1 6

    */


    return 0;
}