PHP Challenges: Check whether a given positive integer is a power of four

PHP Challenges - 1: Exercise-3 with Solution

Write a PHP program to check whether a given positive integer is a power of four.

Input : 4

Explanation :

Sample Solution :

PHP Code :

<?php
// Function to check if a number is a power of four
function is_Power_of_four($n)
{
    // Assign $n to a variable $x for manipulation
    $x = $n;

    // Loop until $x is divisible by 4
    while ($x % 4 == 0) {
        // Divide $x by 4
        $x /= 4;
    }

    // Check if $x is equal to 1 after the loop
    if ($x == 1) {
        // If true, $n is a power of 4
        return "$n is power of 4";
    } else {
        // If false, $n is not a power of 4
        return "$n is not power of 4";
    }
}

// Testing the function with different inputs
print_r(is_Power_of_four(4)."\n");
print_r(is_Power_of_four(36)."\n");
print_r(is_Power_of_four(16)."\n");
?>

Explanation:

Here is a brief explanation of the above PHP code:

• Define a function named 'is_Power_of_four' that takes a single parameter '$n', which is the number to be checked for being a power of four.
• Inside the function:
• It assigns the value of '$n' to a variable '$x'.
• It enters a while loop that continues as long as '$x' is divisible by 4. Inside the loop, it divides '$x' by 4 in each iteration.
• After the loop, it checks if '$x' is equal to 1. If it is, then '$n' is a power of 4, so it returns a string indicating that. Otherwise, it returns a string indicating that '$n' is not a power of 4.
• Finally, the function is tested with three different values (4, 36, and 16) using the 'print_r' function to display the results of each test.

Sample Output:

4 is power of 4                                             
36 is not power of 4                                        
16 is power of 4

Flowchart:

PHP Code Editor:

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