C++ Program to Check Number is Armstrong or Not

To understand C++ program to check Armstrong number, you must know - C++ looping

If the sum of cube of an positive integer is equal to that positive integer, then positive integer is called an Armstrong number. 

For example:

407=4*4*4+0*0*0+7*7*7 //Armstrong number

123 is not equal to 1*1*1+2*2*2+3*3*3 //Not an Armstrong number

C++ Program to Check Number is Armstrong or Not

#include<iostream>

using namespace std;

int main()

{

    int num,n,d,s=0;

    cout<<"Enter a number : ";

    cin>>num;

    n=num;

    while(num!=0)

    {

        d=num%10;

        s=s+d*d*d;

        num/=10;

    }

    if(s==n)

        cout<<endl<<n<<" is an Armstrong number";

    else

        cout<<endl<<n<<" is not an Armstrong number";

    return 0;

}

OUTPUT 1:

Enter a number : 407

407 is an Armstrong number

OUTPUT 2:

Enter a number : 123

123 is not an Armstrong number