C++ program to check happy number

/*Following program checks whether a number is happy number or not. Happy Number Example: 19. If the number's digits squared and added till we get 1, the number is happy number*/
#include<iostream.h>
#include<math.h>
long func(long);
void main()
{
long a;
cout<<"\tEnter a number\n";
cin>>a;
long y=func(a);
if(y==1)
cout<<"Happy Number";
else
cout<<"Unhappy Number\n";

}

long func(long x)
{
 long sum=0,rem;
 while(x>0)
 {
 rem=x%10;
 sum=sum+pow(rem,2);
 x=x/10;
 }
if(sum>10)
func(sum);
else
return sum;
}

OUTPUT: