C++ Program to Check Armstrong Number

In this post, you will learn how to Check Armstrong Number using C++ programming language.

This lesson will teach you how to Check Armstrong Number, with a while loop, assignment operator and decision making statement using the C++ Language. Let’s look at the below source code.

How to Check Armstrong Number?

Source Code

#include <iostream>  
using namespace std;  
int main()  
{  
    int n,r,sum=0,temp;    
    cin>>n; 
    cout<<"Enter the Number = "<<n<<endl;    
    temp=n;   
    while(n>0)    
    {    
        r=n%10;    
        sum=sum+(r*r*r);    
        n=n/10;    
    }   
    if(temp==sum)    
    cout<<"\n"<<temp<<" is a Armstrong Number."<<endl;    
    else    
    cout<<"\n"<<temp<<" is not a Armstrong Number."<<endl;   
    return 0;  
}  

Input

370

Output

Enter the Number = 370
370 is a Armstrong Number.

The statements #include<iostream>, using namespace std, int main are the main factors that support the function of the source code. Now we can look into the working and layout of the code’s function.

1. An Armstrong number, also known as narcissistic number, is a number that is equal to the sum of the cubes of its own digits. For example, 370 is an Armstrong number since 370 = 3*3*3 + 7*7*7 + 0*0*0 . 
2. Declare the variables and strings n,r,sum,tempan integers and assign the value 0 to sum.
3. Collect the number from the user and store it in n using function cin>>  and display the value using cout<< and the Insertion Operators'<<‘ , ‘>>’.
4. Using the assignment operator assign temp=n and create a while loop with the condition (n>0)
5. Create the loop statement with the following functions r=n%10 to find the reminder of n and 10 and store the value in r, perform the mathematical function sum=sum+(r*r*r)and store the value in sum.
6. n=n/10 is the final function in the loop statement and the answer is stored in n.
7. The loop is executed multiple times until the condition is false and the loop is exited.
8. Using the decision making if else statement with the condition (temp==sum) , display the respective output statement according to whether the condition is satisfied or not.

Note: The ‘ << endl ‘ in the code is used to end the current line and move to the next line and ‘\n’ is also a new line function, to understand how both the functions work exclude it from the code, move it around and work with it.