Go – Armstrong Number

In this tutorial, we will learn how to check if a number is an Armstrong number using the Go programming language (Golang). We will explain the concept of an Armstrong number, provide a detailed algorithm, and write a program to determine whether a given number is an Armstrong number.

What is an Armstrong Number?

An Armstrong number (or Narcissistic 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: \( 1^3 + 5^3 + 3^3 = 153 \) (Armstrong number)
  • 9474: \( 9^4 + 4^4 + 7^4 + 4^4 = 9474 \) (Armstrong number)
  • 123: \( 1^3 + 2^3 + 3^3 = 36 \) (Not an Armstrong number)

Logic to Check Armstrong Number

The steps to determine whether a number is an Armstrong number are as follows:

  1. Find the number of digits in the number (denoted as n).
  2. Separate the digits of the number.
  3. Raise each digit to the power of n and sum the results.
  4. Compare the sum with the original number. If they are equal, the number is an Armstrong number.

Example Program to Check Armstrong Number

Program – example.go

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package main

import (
    "fmt"
    "math"
)

func isArmstrong(number int) bool {
    original := number
    sum := 0
    digits := 0

    // Calculate the number of digits
    temp := number
    for temp != 0 {
        digits++
        temp /= 10
    }

    // Calculate the sum of each digit raised to the power of digits
    temp = number
    for temp != 0 {
        digit := temp % 10
        sum += int(math.Pow(float64(digit), float64(digits)))
        temp /= 10
    }

    // Check if the sum is equal to the original number
    return sum == original
}

func main() {
    // Input number
    var num int
    fmt.Print("Enter a number: ")
    fmt.Scan(&num)

    // Check and display result
    if isArmstrong(num) {
        fmt.Println(num, "is an Armstrong number.")
    } else {
        fmt.Println(num, "is not an Armstrong number.")
    }
}

Explanation of Program

  1. Calculate the number of digits: – A temporary variable (temp) is used to count the digits by repeatedly dividing the number by 10.
  2. Compute the sum: – Each digit is extracted using the modulus operator (%), raised to the power of the number of digits using the math.Pow function, and added to a running total (sum).
  3. Check the Armstrong condition: – The computed sum is compared to the original number.
  4. Output the result: – The result is printed, indicating whether the input number is an Armstrong number or not.

Output