Example: Armstrong Number in C++ using Function

// Armstrong Number in C++ using Function
#include <bits/stdc++.h>
#include <cmath>
using namespace std;

// This function will check input number is Armstrong or not
void CheckArmstrong(int p) {
    int q, rem, n = 0;
    float r = 0.0;

    // q - To store the storage of original input number to check
    // rem - To store the reminder
    // r - To store the result variable

    q = p;

    // store the number of digits of x in n
    for (q = p; q != 0; ++n) {
        q /= 10;
    }

    for (q = p; q != 0; q /= 10) {
        rem = q % 10;
        // store the sum of the power of individual digits in r
        r += pow(rem, n);
    }

    // if "p" is equal to "r", the number is an Armstrong number
    if ((int) r == p) {
        cout << p << " is an Armstrong number.\n";
    } else {
        cout << p << " is not an Armstrong number.\n";
    }
}

// It's the driver function
int main() {
    int x; // To store the input number

    cout << "-----Enter the integer number-----\n";
    cin >> x;

    // It will produce the final output
    CheckArmstrong(x);
    
    return 0;
}