Skip to content

IP-16.c

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

Metadata

Property Detail
Author Amit Dutta amitdutta4255@gmail.com
Date 03 Jan 2026
License MIT License (See the LICENSE file for details)
Difficulty Beginner (index: 2 / 10)

Concepts

Beta Feature

This concept detection system is still in beta and may occasionally show incorrect or incomplete results.

  • Recursion
  • Iteration

Actions

Raw View on GitHub

You can print or save this file by opening Raw and using your browser.

Source Code

#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;
}

Explanation

Explain with AI

Copy the prompt below and paste it into any AI assistant.

    You are explaining a C programming code to a beginner.

    STRICT RULES:

    - Only use the given code. Do NOT assume anything not present.

    - Do NOT add extra examples.

    - Keep explanation clear and short.

    - If something is unclear, say "Not clear from code".

    - Follow the exact format below. Do NOT change headings.

    FORMAT:

    [START]

    ## What it does

    (Explain the overall purpose in 1-2 sentences)

    ## Step-by-step

    (Explain how the code works in steps, simple language)

    ## Key Concepts

    (List concepts like loop, condition, function, etc.)

    ## Notes

    (Mention any limitations, errors, or assumptions)

    [END]

    CODE (IP-16.c):

    #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;
    }