PHP Check if Given Number is Perfect Square

Given a number, the task is to check the given number is a perfect square in PHP. A perfect square is an integer that is the square of another integer. For example, 16 is a perfect square because it is the square of 4.

Examples:

Input: num = 16
Output: Perfect Square

Input: 18
Output: Not a Perfect Square

These are the following approaches:

Approach 1: Using the sqrt() Function

The basic method to check if a number is a perfect square is by using the sqrt() function, which returns the square root of a number. If the square root is an integer, then the number is a perfect square.

Example: The isPerfectSquare() function takes an integer $number as an argument and calculates its square root using the sqrt() function. It then checks if the square root is equal to the floor value of the square root (floor($sqrt)). If they are equal, the number is a perfect square.

PHP

<?php

function isPerfectSquare($number) {
    $sqrt = sqrt($number);
    return $sqrt == floor($sqrt);
}

$n = 16;

if (isPerfectSquare($n)) {
    echo "$n is a perfect square.";
} else {
    echo "$n is not a perfect square.";
}

?>

Output

16 is a perfect square.

Approach 2: Using a Loop

Another method to check if a number is a perfect square is by using a loop to find a number whose square is equal to the given number.

Example: The isPerfectSquare() function iterates through numbers starting from 1 and checks if the square of the current number ($i * $i) is equal to the given number. If it finds such a number, the function returns true, indicating that the number is a perfect square. Otherwise, it returns false.

PHP

<?php

function isPerfectSquare($number) {
    for ($i = 1; $i * $i <= $number; $i++) {
        if ($i * $i == $number) {
            return true;
        }
    }
    return false;
}

$n = 16;

if (isPerfectSquare($n)) {
    echo "$n is a perfect square.";
} else {
    echo "$n is not a perfect square.";
}

?>

Output

16 is a perfect square.