armstrong_bwt_nos.c

#include <math.h>
#include <stdio.h>
int main()
{
    int low, high, number, originalNumber, rem, count = 0;
    double result = 0.0;
    printf("Enter two numbers(intervals): ");
    scanf("%d %d", &low, &high);
    printf("Armstrong numbers between %d and %d are: ", low, high);

    // swap numbers if high < low
    if (high < low)
    {
        high += low;
        low = high - low;
        high -= low;
    }

    // iterate number from (low + 1) to (high - 1)
    // In each iteration, check if number is Armstrong
    for (number = low + 1; number < high; ++number)
    {
        originalNumber = number;

        // number of digits calculation
        while (originalNumber != 0)
        {
            originalNumber /= 10;
            ++count;
        }

        originalNumber = number;

        // result contains sum of nth power of individual digits
        while (originalNumber != 0)
        {
            rem = originalNumber % 10;
            result += pow(rem, count);
            originalNumber /= 10;
        }

        // check if number is equal to the sum of nth power of individual digits
        if ((int)result == number)
        {
            printf("%d ", number);
        }

        // resetting the values
        count = 0;
        result = 0;
    }

    return 0;
}