# C# Program to Check Whether the Entered Number is an Armstrong Number or Not

CsharpServer Side ProgrammingProgramming

For an Armstrong number, let us say a number has 3 digits, then the sum of cube of its digits is equal to the number itself.

For example, 153 is equal to −

1³ + 3³ + 5³

To check for it using C#, check the value and find its remainder. Here “val” is the number you want to check for Armstrong −

for (int i = val; i > 0; i = i / 10) {
rem = i % 10;
sum = sum + rem*rem*rem;
}

Now compare the addition with the actual value. If it matches, that would mean the sum of cubes are the same and it is an Armstrong number −

if (sum == val) {
Console.Write("Armstrong Number");
}else {
Console.Write("Not an Armstrong Number");
}

## Example

Let us see a complete example to check whether a number is Armstrong or not.

Live Demo

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
namespace Demo {
class ApplicationNew {
static void Main(string[] args) {
int val = 153, sum = 0;
int rem;
// check for armstrong
for (int i = val; i > 0; i = i / 10) {
rem = i % 10;
sum = sum + rem*rem*rem;
}
if (sum == val) {
Console.Write("Armstrong Number");
} else {
Console.Write("Not an Armstrong Number");
}
}
Armstrong Number