#include <iostream>
#include <iterator>
#include <vector>
#include <algorithm>

using namespace std; 
class A { 
    int i; 
public: 
    A() { 
    }; 
    A(const A& a) { 
        i = a.i; 
        cout << "copy constructor invoked" << endl; 
    }; 
    A(int num) { 
        i = num; 
    }; 
    A& operator = (const A&a) { 
        i = a.i; 
//      cout << "assignment operator invoked" << endl; 
        return *this;
    }; 
    ~A() { 
        cout << "destructor called" << endl; 
    }; 
    friend ostream& operator << (ostream & out, const A& a); 
    friend istream& operator >> (istream &in, A&a); 
}; 
 
ostream & operator << (ostream &out, const A& a) { 
    out << a.i; 
    return out; 
} 
 
istream & operator >> (istream & in, A&a) { 
    in >> a.i; 
    return in; 
 
} 
int main() { 
    vector<A> vA; 
    copy(istream_iterator<A>(cin), istream_iterator<A>(), back_inserter(vA)); 
//  copy(vA.begin(), vA.end(), ostream_iterator<A>(cout, "\t")); 
    return 0; 
} 

copy constructor invoked
copy constructor invoked
copy constructor invoked
copy constructor invoked
copy constructor invoked
copy constructor invoked
copy constructor invoked
copy constructor invoked
destructor called
destructor called
destructor called
destructor called
destructor called
destructor called
destructor called
destructor called
destructor called
destructor called