C/C++ Program to find a given number is STRONG (or) not.

//Program to find a given number is STRONG or not.
#include<iostream>
using namespace std;
int main()
{
       int a;
       cout<<"\n enter a number:";
       cin>>a;
       int i,f,r,sum=0,num;
       num=a;
       while(num>0)
        {
          i=1;f=1;
           r=num%10;
           while(i<=r)
                    {
            f=f*i;
            i++;
            }
        sum=sum+f;
        num=num/10;
           }
           if(sum==a)
        cout<<" Yes, "<<a<<" is a strong number."<<endl;
       else
        cout<<"No, "<<a<<"is not a strong number "<<endl;
return 0;
}