C++ program that shows the list of Armstrong numbers in a range

#include<iostream>
#include<cmath>
using namespace std;

int main()
{
int first,last,digits,Num,sum,countF,countN;
double forPower;
cout << "Enter first number: ";
cin >> first;
cout << "Enter last number of range: ";
cin >> last;
digits=first;
countF=0;
while( digits!=0 )
{
countF++;
digits/=10;
}
cout << "Amstrongs from "
<< first
<< " to "
<< last
<< " are: ";
Num=first;
while(Num<=last)
{
sum=0;
digits=Num;
while(digits!=0)
{
forPower=digits%10;
sum+=pow(forPower,countF);
digits/=10;
}
if(sum==Num)
cout << " " << Num;
Num++;
countN=0;
digits=Num;
while(digits!=0)
{
countN++;
digits/=10;
}
if(countN>countF)
countF++;
}
cout << endl;

return 0;
}