Logic: An Armstrong number is a number which is equal to the sum of digits raise to the power total number of digits in the number. Some Armstrong numbers are: 0, 1, 2, 3, 153, 370, 407, 1634, 8208, etc.
Algorithm:
- First calculate the number of digits in a program
- Then compute the sum of individual digits raise to the power number of digits
- If this sum equals the input number, then the number is an Armstrong number otherwise not
#include <stdio.h>
#include<conio.h>
int power(int, int);
void main()
{
int n, sum = 0, temp, remainder, digits = 0;
clrscr();
printf("Input an integer\n");
scanf("%d", &n);
temp = n;
// Count number of digits
while (temp != 0)
{
digits++;
temp = temp/10;
}
temp = n;
while (temp != 0)
{
remainder = temp%10;
sum = sum + power(remainder, digits);
temp = temp/10;
}
if (n == sum)
printf("%d is an Armstrong number.\n", n);
else
printf("%d isn't an Armstrong number.\n", n);
getch();
}
int power(int n, int r)
{
int c, p = 1;
for (c = 1; c <= r; c++)
p = p*n;
return p;
}
