PHP for loop Exercises: Calculate and print the factorial of a number using a for loop

Last update on May 31 2025 12:57:08 (UTC/GMT +8 hours)

5. Factorial Calculation

Write a program to calculate and print the factorial of a number using a for loop. The factorial of a number is the product of all integers up to and including that number, so the factorial of 4 is 4*3*2*1= 24.

Visual Presentation:

PHP for loop Exercises: Calculate and print the factorial of a number using a for loop

Sample Solution:

PHP Code:

<?php
// Set the value of n to 6
$n = 6;

// Initialize variable x to store the factorial value
$x = 1;

// Loop to calculate the factorial of n
for($i = 1; $i <= $n - 1; $i++)
{
    // Calculate factorial iteratively
    $x *= ($i + 1); 
}

// Print the factorial of n
echo "The factorial of  $n = $x"."\n";
?>

Output:

The factorial of  6 = 720

Explanation:

In the exercise above,

The code begins with a PHP opening tag <?php.
It sets the variable '$n' to 6, representing the number whose factorial is to be calculated.
Another variable '$x' is initialized to 1. This variable stores the factorial value.
A "for" loop calculates the factorial. It iterates from 1 to n-1 ($i=1; $i<=$n-1; $i++), as the factorial of 'n' is calculated by multiplying all positive integers up to n.
Inside the loop, each iteration multiplies the current value of '$x' by the next integer, starting from 1 up to 'n'.
After the loop completes, the calculated factorial value is printed using "echo", along with a message indicating the number whose factorial is calculated ("The factorial of $n = $x").
Finally, PHP code ends with a closing tag ?>.

Flowchart:

For more Practice: Solve these Related Problems:

Write a PHP script to calculate the factorial of a given number using a for loop and display intermediate multiplication steps.
Write a PHP function that computes factorial recursively and compares its performance with a for loop implementation.
Write a PHP program that calculates and prints the factorial of a number, then outputs the result's number of digits.
Write a PHP script to compute the factorial of a number and use error handling to manage non-positive inputs.

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PHP Code Editor:

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