Polymorphism/Function Overloading

Program to attain polymorphism through Function Overloading :-

#include<iostream.h>
#include<conio.h>

void sum(int a,int b)
 {
    cout<<"\nSum of the numbers is : "<<(a+b);
   }

int sum(int a, int b, int c)
 {
    return(a+b+c);
   }

void main()
 {
      int a,b,c,x;
      menu:
    cout<<"\nEnter number of terms you want to add (2/3) : ";
      cin>>x;
      if(x==2)
       {
          cout<<"\nEnter the terms to be added : ";
            cin>>a>>b;
            sum(a,b);
         }
      if(x==3)
       {
          cout<<"\nEnter the terms to be added : ";
            cin>>a>>b>>c;
            cout<<"\nSum of the terms is : "<<sum(a,b,c);
         }
      goto menu;
      getch();
   }