Armstrong_no.c

// C program to find Armstrong number

#include <stdio.h>

/* Function to calculate x raised to the power y */
int power(int x, unsigned int y)
{
	if (y == 0)
		return 1;
	if (y % 2 == 0)
		return power(x, y / 2) * power(x, y / 2);
	return x * power(x, y / 2) * power(x, y / 2);
}

/* Function to calculate order of the number */
int order(int x)
{
	int n = 0;
	while (x) {
		n++;
		x = x / 10;
	}
	return n;
}

// Function to check whether the given number is
// Armstrong number or not
int isArmstrong(int x)
{
	// Calling order function
	int n = order(x);
	int temp = x, sum = 0;
	while (temp) {
		int r = temp % 10;
		sum += power(r, n);
		temp = temp / 10;
	}

	// If satisfies Armstrong condition
	if (sum == x)
		return 1;
	else
		return 0;
}

// Driver Program
int main()
{
	int x = 153;
	if (isArmstrong(x) == 1)
		printf("True\n");
	else
		printf("False\n");

	x = 1253;
	if (isArmstrong(x) == 1)
		printf("True\n");
	else
		printf("False\n");

	return 0;
}