C++ Program to check Armstrong Number

An integer number is called Armstrong number if sum of the cubes of its digits is equal to the number itself. For example:
370 is an armstrong number because:

370 = 3*3*3 + 7*7*7 + 0*0*0
    = 27 + 343 + 0
    = 370

Example: Check Armstrong Number using For loop

To understand this program, you should have the knowledge of for loop and if-else statement.

#include <iostream>
using namespace std;

int main() {
   int num, sum = 0, digit;
   cout<<"Enter a positive integer: ";
   cin>>num;

   for(int temp=num; temp!=0;){
      digit = temp % 10;
      sum = sum +(digit * digit * digit);
      temp = temp/10;
   }

   if(sum == num)
      cout<<num<<" is an Armstrong number.";
   else
      cout<<num<<" is not an Armstrong number.";

   return 0;
}

Output:

Enter a positive  integer: 370
370 is an Armstrong number.

You can also use while loop instead of for loop to check the Armstrong number:
Replace this part of the code:

for(int temp=num; temp!=0;){
    digit = temp % 10;
    sum = sum +(digit * digit * digit);
    temp = temp/10;
}

with this:

int temp = num;
while(temp != 0)
{
   digit = temp % 10;
   sum = sum +(digit * digit * digit);
   temp = temp/10;
}