PHP Challenges: Reverse the digits of an integer

Last update on December 20 2024 10:22:15 (UTC/GMT +8 hours)

Write a PHP program to reverse the digits of an integer.

Explanation :

PHP: Reverse the digits of an integer

Sample Solution :

PHP Code :

<?php
// Function to reverse an integer
function reverse_integer($n)
{
    // Initialize variable to store the reversed integer
    $reverse = 0;
    
    // Loop until the input number becomes 0
    while ($n > 0)
    {
        // Multiply the current reversed number by 10 and add the last digit of the input number
        $reverse = $reverse * 10;
        $reverse = $reverse + $n % 10;
        
        // Remove the last digit from the input number
        $n = (int)($n / 10);
    }
    
    // Return the reversed integer
    return $reverse;
}   

// Test the reverse_integer function with different inputs and print the results
print_r(reverse_integer(1234) . "\n");
print_r(reverse_integer(23) . "\n");
?>

Explanation:

Here is a brief explanation of the above PHP code:

Function definition:

The code defines a function named "reverse_integer()" which reverses an integer. It takes a single parameter '$n', which is the integer to be reversed.

Inside the function:

It initializes a variable '$reverse' to store the reversed integer.
It enters a "while" loop that continues until the input number '$n' becomes 0.
Within each iteration of the loop:

It multiplies the current reversed number '$reverse' by 10 and adds the last digit of the input number ($n % 10).
It removes the last digit from the input number by integer division ($n / 10).

After the loop, it returns the reversed integer stored in '$reverse'.

Function Call & Testing:

The "reverse_integer()" function is called twice with different input integers (1234 and 23).
The results of the function calls are printed using "print_r()", which displays the reversed integers.

Sample Output:

4321                                                        
32

Flowchart:

PHP Code Editor:

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