#include <iostream> 
#include <vector>
using namespace std;

class Base
{
public:
      void Display( void )
      {
            cout<<"Base display"<<endl;
      }

      int Display( int a )
      {
            cout<<"Base int display"<<endl;
            return 0;
      }

};

class Derived : public Base
{
public:

      void Display( void )
      {
            cout<<"Derived display"<<endl;
      }
};


void main()
{
   Derived obj;
   obj.Display();  
   obj.Display( 10 );
}

$test1.cpp: In function ‘int main()’:
test1.cpp:35: error: no matching function for call to ‘Derived::Display(int)’
test1.cpp:24: note: candidates are: void Derived::Display()

On commenting obj.Display(10), it works.