Check Armstrong Number using user-defined function

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AAn integer number is called Armstrong number if sum of the cubes of its digits is equal to the number itself. For example, 371 is an Armstrong number since 3*3*3 + 7*7*7 + 1*1*1 = 371.

Lets write a program to check whether the input number is armstrong number using user-defined function. If you are looking for a program to check armstrong number using loop then see: C++ Program to check Armstrong number using for loop.

Example: Check whether input number is Armstrong Number or not

#include <iostream>  
using namespace std;  
bool checkArmstrongNumber(int num);    
int main(){
     int num;
     bool flag;
     cout<<"Enter a positive  integer: ";
       //Calling function
     flag = checkArmstrongNumber(num);
     if(flag == true)
        cout<<num<<" is an Armstrong number.";
        cout<<num<<" is not an Armstrong number.";
       return 0;
  /* User defined function that checks whether the passed
   * integer number is Armstrong or not   */
  bool checkArmstrongNumber(int num) {
     int temp, sum=0, digit;
     bool isArm;
       temp = num;
     while(temp != 0) {
        digit = temp % 10;
        sum = sum +(digit * digit * digit);
        temp = temp/10;
    if (sum==num)
        isArm = true;
        isArm = false;
       return isArm;


Enter a positive  integer: 371
371 is an Armstrong number.

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