PHP Program to Check Armstrong Number

Posted in PHP Tutorial

Updated on Jan 11, 2024

By Mari Selvan

👁️ 164 - Views

⏳ 4 mins

💬 1 Comment

Photo Credit to CodeToFun

🙋 Introduction

In the realm of programming, solving mathematical problems is a common task. One such interesting problem is checking whether a given number is an Armstrong number.

Armstrong numbers, also known as narcissistic numbers or pluperfect digital invariants, are numbers that are the sum of their own digits each raised to the power of the number of digits.

In this tutorial, we will explore a PHP program designed to check whether a given number is an Armstrong number. The program involves calculating the sum of the digits raised to the power of the number of digits and comparing it with the original number.

📄 Example

Let's delve into the PHP code that accomplishes this task.

findAverage.html

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<?php

// Function to check if a number is an Armstrong number
function isArmstrong($number) {
    $originalNumber = $number;
    $n = 0;
    $result = 0;

    // Count the number of digits
    while ($originalNumber != 0) {
        $originalNumber /= 10;
        $n++;
    }

    // Reset originalNumber to the actual number
    $originalNumber = $number;

    // Calculate the sum of nth power of individual digits
    while ($originalNumber != 0) {
        $remainder = $originalNumber % 10;
        $result += pow($remainder, $n);
        $originalNumber /= 10;
    }

    // Check if the result is equal to the original number
    return $result == $number;
}

// Driver program
// Replace this value with the number you want to check
$number = 153;

// Call the function to check if the number is Armstrong
if (isArmstrong($number)) {
    echo "$number is an Armstrong number.\n";
} else {
    echo "$number is not an Armstrong number.\n";
}

?>

💻 Testing the Program

To test the program with different numbers, modify the value of $number in the code.

Output

153 is an Armstrong number.

🧠 How the Program Works

The program defines a function isArmstrong that takes an integer $number as input and checks whether it is an Armstrong number.
Replace the value of $number in the main program with the desired number you want to check.
The program calls the isArmstrong function and prints the result.

📏 Between the Given Range

Let's delve into the PHP code that checks for Armstrong numbers in the specified range.

isArmstrong.php

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<?php
// Function to check if a number is an Armstrong number
function isArmstrong($number)
{
  $originalNumber = $number;
  $sum = 0;
  $digits = strlen($number);

  while ($number > 0)
  {
    $digit = $number % 10;
    $sum += pow($digit, $digits);
    $number = (int)($number / 10);
  }

  return $sum === $originalNumber;
}

// Check Armstrong numbers in the range 1 to 50
echo "Armstrong numbers in the range 1 to 50 are:\n";

for ($i = 1;$i <= 50;++$i)
{
  if (isArmstrong($i))
  {
    echo "$i, ";
  }
}

?>

💻 Testing the Program

Output

Armstrong numbers in the range 1 to 50 are:
1, 2, 3, 4, 5, 6, 7, 8, 9,

The program is designed to check Armstrong numbers in the range 1 to 50. Simply run the script to see the Armstrong numbers within this range.

🧠 How the Program Works

The program defines a function isArmstrong that checks whether a given number is an Armstrong number.
Inside the function, it calculates the sum of each digit raised to the power of the number of digits.
The main section then iterates through the numbers in the range 1 to 50 and prints the Armstrong numbers.

🧐 Understanding the Concept of Armstrong Number

Before delving into the code, let's understand the concept behind Armstrong numbers. An Armstrong number is a number that is 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.

🎢 Optimizing the Program

While the provided program is straightforward, consider exploring and implementing alternative approaches or optimizations for checking Armstrong numbers.

Feel free to incorporate and modify this code as needed for your specific use case. Happy coding!