PHP function Exercises: Create a function to calculate the factorial of positive a number

Last update on May 31 2025 12:56:51 (UTC/GMT +8 hours)

1. Factorial Function

Write a PHP function to calculate the factorial of a number (a non-negative integer). The function accepts the number as an argument.

Visual Presentation:

PHP function Exercises: Create a function to calculate the factorial of positive a number

Sample Solution:

PHP Code:

<?php
// Function to calculate the factorial of a number
function factorial_of_a_number($n)
{
    // Base case: if n is 0, return 1 (factorial of 0 is 1)
    if ($n == 0)
    {
        return 1;
    }
    else
    {
        // Recursive call: calculate factorial by multiplying n with factorial of (n-1)
        return $n * factorial_of_a_number($n - 1);
    }
}

// Call the function and print the result
print_r(factorial_of_a_number(4) . "\n");
?>

Output:

Explanation:

In the exercise above,

Define a function named "factorial_of_a_number()" which takes an integer parameter '$n'.
Inside the function, there's a conditional check to handle the base case: if the input number '$n' is 0, the function returns 1, as the factorial of 0 is defined to be 1.
If the input number is not 0, the function recursively calls itself with the argument '$n - 1' and multiplies the result with '$n'.
The recursive calls continue until the base case is reached (i.e., '$n' becomes 0), at which point the function returns 1.
Outside the function definition, the "factorial_of_a_number()" function is called with an argument of 4, which calculates the factorial of 4.
The result is then printed using "print_r()", followed by a newline character ("\n").

Flowchart :

For more Practice: Solve these Related Problems:

Write a PHP function to compute the factorial of a number using a recursive approach, ensuring proper error handling for negative inputs.
Write a PHP script to calculate the factorial of a number iteratively and then compare the result with a built-in mathematical formula for large numbers.
Write a PHP function to compute factorial values for an array of numbers and return the results in an associative array with the original numbers as keys.
Write a PHP program to compute the factorial of a number using a tail-recursive function and output the recursion depth alongside the result.

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PHP Code Editor:

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