C++ Program that Add Sum of Two numbers using two function

C++ Program that Add Sum of Two numbers using two function 

#include <iostream>

using namespace std;
int sum(int a,int b);
int main()
{
 int x;
 int a,b;
cout<< " Enter the first Number : ";
cin>>a;
cout<< " Enter the first Number : ";
cin>>b;


 x=sum(a,b);

cout<< a<<" + " <<b<<" = "<<x<<endl;
    return 0;
}
int sum(int a, int b){
int c = a+b;

return c;

}