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

using namespace std ;

class student
{
	public:
	 int id  ;
	 student( )
	  {
		  id=0 ;
      }
	 student( int idP )
	  {
		  id = idP ;
	  }
	 student( const student& obj1 )
	  {
		  id = obj1.id ;
	  }

	 ~student(  )
	  {
	  }

};

bool studentCompareFunction (student obj1, student obj2  )
{
	return ( obj1.id < obj2.id);
}

class studentCompareClass
{
   public:
     bool ascend = true ;
     bool operator() (student obj1, student obj2  )
     {
		 if ( ascend )
		   return ( obj1.id < obj2.id) ;
		 else
		    return ( obj2.id < obj1.id) ;
	 }
} ;



int main()
{
    student  studentObject1(1)  ;
    student  studentObject2(2)  ;
    student  studentObject3(3)  ;
    vector< student >   vec ;


    vec.push_back( studentObject1 ) ;
    vec.push_back( studentObject3 ) ;
    vec.push_back( studentObject2 ) ;
    studentCompareClass studentCompareClassObj1 ;
    studentCompareClassObj1.ascend = false ;
    sort( vec.begin() , vec.end() ,  studentCompareClassObj1  ) ;
    for( student x1 : vec )
      cout << x1.id << " " ;
    cout << endl ;

    vec.clear() ;
    vec.push_back( studentObject1 ) ;
    vec.push_back( studentObject3 ) ;
    vec.push_back( studentObject2 ) ;
    sort( vec.begin() , vec.end() ,  studentCompareFunction  ) ;
    for( student x1 : vec )
      cout << x1.id << " " ;
    cout << endl ;



    return 0 ;
}