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### C Program to Check Whether a Number is Armstrong or Not

Write a c program to check whether a number is Armstrong or not. In this program, we take an input number from a user and check whether an input number is Armstrong or not.

Before we start solving this problem, let's understand what is Armstrong number?

## What is Armstrong number?

An Armstrong number is an n-digit number that is equal to the sum of the nth powers of its digits.

For example - 153 , 371 is an Armstrong number.

Example 1 - 153 has 3 digits.

153 : 1 3 + 5 3 ;+ 3 3 = 153

Example 2 - Take an example of 6 which has 1 digit.

6 : 6 = 6  It's an Armstrong number

Example 3 -  Take another example let's say 15, it has 2 digits.

15 : 12 + 52 = 26

So 15 is not an Armstrong number.

Example 4 - This time let's take bigger number 1634, it has 4 digits.

1634 : 1 4 + 6 4 + 3 4 + 4 4 = 1634

It's an Armstrong number.

We have understood the concept, let's solve this problem.

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## C Program to Check Whether a Number is Armstrong or Not

In this example, we first take an input number. Then we find the length of a number and then calculate the sum of a number (Which i have explained in examples).  If entered number and the sum of a number is equal then it's an Armstrong number.

C program to calculate the sum of digits of a number

```#include <stdio.h>
#include <math.h>

int main() {

int num, remainder, temp, sum = 0, n = 0;

//Take input number
printf("Enter a number");
scanf("%d", &num);

temp = num;

//Find the length of a number
while(temp > 0) {
n++;
temp = temp/10;
}

//Again assign temp
temp = num;

while(temp > 0){

remainder = temp % 10;

sum  = sum + pow(remainder, n);
temp = temp/10;
}

if (num == sum){
printf("\n %d is an Armstrong number ", num);

} else {
printf ("\n %d is not an Armstrong number ", num);

}

return 0;
}

```

Output -

Enter a number : 153

153 is an Armstrong number

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