C Program to Generate Armstrong Numbers in Given Minimum to Maximum Ranges

A number is said to be Armstrong or Narcissistic Number if it is equal to the sum of its own digits raised to the power of the number of digits in a given number.

For example number 153 is Armstrong number because: 1³ + 5³ + 3³ = 153

Similary, 1634 is also Armstrong number i.e. 1⁴+6⁴+3⁴+4⁴ = 1634

Single digits number 1 to 9 are also Armstrong numbers.

In this C program we are going to generate such Armstrong numbers in ranges from maximum to minimum, where minimum and maximum values are given by user.

Program

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

int main()
{
	 int minimum, maximum, digitCount, number, sum, rem, i;
	 clrscr();
	 printf("Enter minimum number: ");
	 scanf("%d", &minimum);
	 printf("Enter maximum number: ");
	 scanf("%d", &maximum);
	
	 for(i=minimum; i<=maximum; i++)
	 {
	
		  /* Finding number of digits */
		  number = i;
		  digitCount = 0;
		  while(number != 0)
		  {
			   digitCount++;
			   number = number/10;
		  }
		
		  /* Finding sum */
		  number = i;
		  sum = 0;
		  while(number != 0)
		  {
			   rem = number%10;
			   sum = sum + pow(rem, digitCount);
			   number = number/10;
		  }
		
		  /* Making Decision and Printing */
		  if(sum == i)
		  {
		   	printf("%d\t", i);
		  }
	 }
	 getch();
	 return(0);
}

Output of the above program :

Enter minimum number: 1 ↲
Enter maximum number: 10000 ↲
1     2     3     4     5     6     7     8     9     153
370   371   407   1634  8208  9474

Note: ↲ indicates enter is pressed.