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

PHP Challenges - 1: Exercise-1 with Solution

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

Input : 4

Visualization of powers of two from 1 to 1024:

Sample Solution :

PHP Code :

<?php
// Function to check if a number is a power of two
function is_Power_of_two($n)
{
    // Check if the bitwise AND of $n and $n - 1 equals 0
    if(($n & ($n - 1)) == 0)
    {
        // If true, $n is a power of 2
        return "$n is power of 2";
    }
    else
    {
        // If false, $n is not a power of 2
        return "$n is not power of 2";
    }
}
// Testing the function with different inputs
print_r(is_Power_of_two(4)."\n");
print_r(is_Power_of_two(36)."\n");
print_r(is_Power_of_two(16)."\n");
?>

Explanation:

Here is a brief explanation of the above PHP code:

• The code defines a function named 'is_Power_of_two' that takes a single parameter '$n', which is the number to be checked.
• Inside the function, it checks if '$n' is a power of two using bitwise operations. Specifically, it checks if the result of the expression '$n & ($n - 1)' equals zero. This expression is true only when '$n' is a power of two.
• If the condition is true, the function returns a string indicating that '$n' is a power of 2. If false, it returns a string indicating that '$n' is not a power of 2.
• 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 2                                             
36 is not power of 2                                        
16 is power of 2

Flowchart:

PHP Code Editor:

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