PHP Program to Check Perfect Number

Posted in PHP Tutorial

Updated on Jan 11, 2024

By Mari Selvan

👁️ 210 - Views

⏳ 4 mins

💬 1 Comment

Photo Credit to CodeToFun

🙋 Introduction

In the realm of programming, exploring the properties of numbers is a fascinating task. One such special type of number is a perfect number.

A perfect number is a positive integer that is equal to the sum of its proper divisors (excluding itself).

In this tutorial, we will explore a PHP program designed to check whether a given number is a perfect number.

📄 Example

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

isPerfectNumber.php

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<?php
// Function to check if a number is a perfect number
function isPerfectNumber($number)
{
  $sumOfDivisors = 0;

  // Iterate through potential divisors up to half of the number
  for ($i = 1;$i <= $number / 2;++$i)
  {
    // If $i is a divisor, add it to the sumOfDivisors
    if ($number % $i === 0)
    {
      $sumOfDivisors += $i;
    }
  }

  // If the sum of divisors equals the original number, it is a perfect number
  return $sumOfDivisors === $number;
}

// Driver program
// Replace this value with the number you want to check
$number = 28;

// Call the function to check if the number is a perfect number
if (isPerfectNumber($number))
{
  echo "$number is a perfect number.\n";
}
else
{
  echo "$number is not a perfect number.\n";
}

?>

💻 Testing the Program

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

Output

28 is a perfect number.

Run the script to check if the specified number is a perfect number.

🧠 How the Program Works

The program defines a function isPerfectNumber that takes an integer $number as input and returns true if the number is a perfect number, and false otherwise.
The function iterates through potential divisors up to half of the number and checks if each divisor divides evenly. If so, it adds the divisor to the sum of divisors.
If the sum of divisors equals the original number, the function returns true, indicating a perfect number.
Inside the main program, replace the value of $number with the desired number you want to check.
The program calls the isPerfectNumber function and prints the result.

📏 Between the Given Range

Let's delve into the php code that identifies perfect numbers in the specified range.

isPerfect.php

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<?php
// Function to check if a number is perfect
function isPerfect($number)
{
  $sum = 0;

  for ($i = 1;$i <= $number / 2;++$i)
  {
    if ($number % $i == 0)
    {
      $sum += $i;
    }
  }

  return $sum == $number;
}

// Display perfect numbers in the range 1 to 50
echo "Perfect Numbers in the range 1 to 50:\n";
for ($i = 2;$i <= 50;++$i)
{
  if (isPerfect($i))
  {
    echo $i . " ";
  }
}

?>

💻 Testing the Program

Output

Perfect Numbers in the range 1 to 50:
6 28

Run the script to see the perfect numbers in the range from 1 to 50.

🧠 How the Program Works

The program defines a function isPerfect that checks if a given number is perfect.
Inside the function, it iterates through the numbers from 1 to half of the given number and accumulates the sum of proper divisors.
The main section of the program displays perfect numbers in the range from 1 to 50 by calling the isPerfect function for each number.

🧐 Understanding the Concept of Perfect Number

Before delving into the code, let's understand the concept of perfect numbers. A perfect number is a positive integer that is equal to the sum of its proper divisors (excluding itself).