#include <bits/stdc++.h>
    using namespace std;
 
    class Base {
      public:
      virtual int function() const {
    	cout << "Base::function()\n";
    	return 1;
      }
      virtual void function(string) const {}
    };
 
 
    class Derived : public Base {
      public:
           // overloading function() of base
           int function(int) const {
             cout << "Derived::function()\n";
             return 4;
        }
    };
 
 
    int main()
    {
    	string s("StackOverflow");
		Derived d;
    	Base* b = &d;
        //calling derived::function() and function(s)    
    	b->function();
    	b->function(s);
    }
 

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