Program in C++ to check a given number is Armstrong or not

Program in C++ to check a given number is Armstrong or not

1 #include<iostream>
 2  #include<conio.h>
 3  #include<math.h>
 4    using namespace std;
 5    int main()
 6       {
 7         int sum=0,r,n,a,as,digits=0;
 8         cout<<"Enter a number:-";
 9         cin>>n;
10         a=as=n;
11         //for count digits of a given number
12         while(n!=0)
13         {
14             n=n/10;
15             digits++;
16         }
17          while(a!=0)
18           {
19              r=a%10;
20              sum+=pow(r,digits);
21              a=a/10;
22           }
23          if(as==sum)
24            cout<<as<<" is Armstrong no.";
25          else
26             cout<<as<<" is not Armstrong no.";
27      getch();
28     }

Output:-