In number theory, a narcissistic number (also known as a pluperfect digital invariant (PPDI), an Armstrong number (after Michael F. Armstrong) or a plus perfect number) in a given number base is a number that is the sum of its own digits each raised to the power of the number of digits.

COMING SOON!

```
// Program to check whether a number is an armstrong number or not
#include <iostream>
using std::cout;
using std::cin;
int main() {
int n, k, d, s = 0;
cout << "Enter a number:";
cin >> n;
k = n;
while (k != 0) {
d = k % 10;
s += d * d * d;
k /= 10;
}
if (s == n)
cout << n << "is an armstrong number";
else
cout << n << "is not an armstrong number";
}
```