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

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

Before going to write the C# program to check whether the number is Armstrong or not, let’s understand what is Armstrong number.

Armstrong number is a number that is equal to the sum of cubes of its digits. For example 0, 1, 153, 370, 371 and 407 are the Armstrong numbers.

Let’s try to understand why 371 is an Armstrong number.

371 = (3*3*3)+(7*7*7)+(1*1*1)
where:
(3*3*3)=27
(7*7*7)=343
(1*1*1)=1
So:
27+343+1=371

Let’s see the C# program to check Armstrong Number

class CodeLerner
{
static void Main(string[] args)
{
int start, end, i, d;
int temp, sum = 0;
Console.WriteLine(“ENter start num:”);
Console.WriteLine(“ENter end num:“);
Console.WriteLine(“arm num are:”);
for (i = start; i <= end; i++)
{
temp = i;
sum = 0;
do
{
d = temp % 10;
sum = sum + d * d * d;
temp = temp / 10;
}
while (temp != 0);
if (i == sum)

Console.WriteLine(” ” + i);
}

OutPut :

```Enter the Number= 371
Armstrong Number.```
```Enter the Number= 342
Not Armstrong Number.``` 