functions with default arguments...

 #include<iostream>

using namespace std;

int main()

{

int sum(int x=1 ,int y=2 , int z=3);

cout << " Sum= "<<sum(10,20,30)<<endl;

cout << " Sum= "<<sum(10,20)<<endl;

  cout << " Sum= "<<sum(10)<<endl;

}

int sum(int x ,int y , int z)

{

return x+y+z;

}