IP-16.c

Metadata

• Author — Amit Dutta
• Last updated — 03 Jan 2026
• License — MIT License (See the LICENSE file for details)

Problem Statement

Problem Statement

Write a C program that includes a user-defined function named isArmstrong with the signature int isArmstrong(int num);. An Armstrong number is a number that is equal to the sum of its own digits each raised to the power of the number of digits. For example, 153 is an Armstrong number because 1^3 + 5^3 + 3^3 = 153

Source Code

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

int isArmstrong(int);
int count(int);

int main()
{
    int n;
    printf("Enter the number: ");
    scanf("%d", &n);

    if (isArmstrong(n))
    {
        printf("\nInput %d is a Armstrong Number.", n);
    }
    else
    {
        printf("\nInput %d is Not a Armstrong Number.", n);
    }

    return 0;
}

int count(int n)
{
    int count = 0;
    while (n > 0)
    {
        count++;
        n = n / 10;
    }
    return count;
}

int isArmstrong(int n)
{
    if (n < 0)
        return 0; 
    if (n == 0)
        return 1;

    int power = count(n);
    int temp = n;
    int checker = 0;

    while (temp > 0)
    {
        int digit = temp % 10;
        checker = checker + (int)round(pow(digit, power));
        temp = temp / 10;
    }
    return n == checker;
}