copy_if

#include <algorithm>
#include <iostream>
#include <vector>
                                                                                                                
using std::vector,
    std::copy_if,
    std::cerr;
                                        
class Temp{
    public:
        int a, b;
        Temp(int i, int j):a(i), b(j){}
};

bool operator==(const Temp& l, const Temp& r)
{
    return l.a == r.a && l.b == r.b;
} 
                        
typedef vector<Temp> my_vector;
            
int main(){
    my_vector a = {Temp(0, 0), Temp(1, 1), Temp(2, 4), Temp(3, 9), Temp(3, 9), Temp(4, 16), Temp(5, 25), Temp(6, 36), Temp(7, 49), Temp(8, 64), Temp(9, 81), Temp(10, 100), Temp(11, 121), Temp(12, 144), Temp(13, 169), Temp(14, 196), Temp(15, 225), Temp(16, 256), Temp(17, 289), Temp(18, 324), Temp(19, 361)};
    my_vector b = {Temp(2, 4), Temp(3, 9), Temp(4, 16)};

    auto print = [] (Temp t){
        cerr << "Temp(" << t.a << ", " << t.b << ")\n";
    };  

    my_vector::iterator start = a.begin();
    my_vector::iterator finish = a.begin();
    advance(start, 3);
    advance(finish, 10);

    my_vector::iterator pos = b.begin();
    advance(pos, 1);
    cerr << "b before copy:\n";
    for_each(b.begin(), b.end(), print);

    auto test = [](Temp a)->bool{
        if(a.a > 4 && a.a < 10){
            return true;
        }
        return false;
    };

    copy_if(start, finish, pos, test);

    cerr << "b after copy:\n";
    for_each(b.begin(), b.end(), print);
    return 0;
}