Find Armstrong number in C++ with logic explanation and code dry run

What is Armstrong number?
A number in which the sum of cube of its individual digits is equal to the number itself is called Armstrong number
For Example: 1^3 + 5^3 + 3^3 = 153
4 * 4 * 4 + 0 * 0 * 0 + 7 * 7 * 7 = 407 is an Armstrong number.

C++ Program

#include<iostream>
  using namespace std;
int main() {
	int armstrong=0,num=0,result=0,check;
	cout<<"Enter Number to find it is an Armstrong number?";
	cin>>num;
	check=num;
	for (int i=1;num!=0;i++) {
		armstrong=num%10;
		num=num/10;
		armstrong=armstrong*armstrong*armstrong;
		result=result+armstrong;
	}
	if(result==check) {
		cout<<check<<"  is an Armstrong Number";
	} else {
		cout<<check<<"  is NOT an Armstrong Number";
	}
	return 0;
}