Program to find the sum of numbers using function overloading

#include<iostream.h>
int sum(int,int);
int sum(int,int,int);
void main()
{
int fun1,fun2;
fun1=sum(3,4);
fun2=sum(4,5,6);
cout<<"Sum(3,4)="<<fun1<<endl;
}
int sum(int a,int b)
{
return(a+b);
}
int sum(int a,int b,int c)
{
return(a+b+c);
}

Output:
Sum(3,4)=7
Sum(4,5,6)=15