практика_пары1_4

#include <algorithm>
#include <utility>
#include <fstream>
#include <vector>
#include <math.h>

using namespace std;


ofstream out("output.txt");

bool diag (pair<int,int> a)
{
        return (a.second == a.first);
}

bool eq(pair<int,int> a, pair <int, int> b)
{
        return a.first < b.first;
}

bool comp (pair<int,int> a)
{
        return (a.first > 0 && a.second < 0);
}

bool comparator(pair <int,int> a, pair <int, int> b)
{

        return ( a.first * a.first + a.second * a.second <  b.first * b.first + b.second * b.second ) ;
}
void fun(pair <int, int> b, int tmp)
{
        if(b.first * b.first + b.second * b.second == tmp)
                out << "(" << b.first << ", " << b.second << ")  ";
}
void print(pair <int, int> a)
{
    out << "(" << a.first << ", " << a.second << ")"<< endl;
}


int main()
{
        ifstream in("input.txt");


        vector <pair<int, int>> vec;
        int n;
        int m;
        while(in.peek() != EOF)
        {
                in >> n>> m;
                vec.push_back(make_pair(n, m));
        }
        vec.erase(remove_if(vec.begin(), vec.end(), comp), vec.end());
        out << "All points without the fourth quater:" << endl;
        for_each(vec.begin(), vec.end(), print);
        out << " count of points on x=y: " << count_if(vec.begin(),vec.end(),diag) << endl;
        vector <pair<int, int>>::iterator it = min_element(vec.begin(), vec.end(), comparator);
        int temp = it->first*(*it).first + it->second * it->second;
        out << "the least distance point(s): ";
        for_each(vec.begin(), vec.end(), bind2nd(ptr_fun(fun), temp));
        out << endl;
        stable_sort(vec.begin(), vec.end(), eq);
        out << " sort:" << endl;
        for_each(vec.begin(), vec.end(), print);
        return 0;
}