05.php

<?php // FUNCTIONS



/**
 * Prints 'Hello, world!'
 */
function hello()
{
    echo '<p>Hello, world!</p>';
}



/**
 * Returns the square of a number
 * @param {Number} x - Number to be squared.
 * @returns {Number} y - Square of x
 */
function square($x)
{
    $y = $x * $x;
    return $y;
}



/**
 * Returns the sum of a and b
 * @param {Number} a - First number.
 * @param {Number} b - Second number.
 * @returns {Number} sum - Sum of a and b
 */
function sum($a, $b)
{
    $sum = $a + $b;
    return $sum;
}



/**
 * Returns the product of a and b
 * @param {Number} a
 * @param {Number} b
 * @param {Boolean} retArr - If set to true, the function will return an array
 * @returns {Number|Array} - Product of a and b or an array that contains a, b and the product of a and b.
 */
function product($a, $b, $retArr) {
    if ($retArr) {
        return [$a, $b, $a * $b];
    }
    return $a * $b;
}



/**
 * Returns the mean of an array of numbers, the square of a number, and an array of strings sorted in alphabetical order.
 * @param {Array} nmbs - Array of numbers
 * @param {Number} n - Number to be squared
 * @param {Array} strs - Array of strings
 * @returns {Array} result - Array that contains the mean of 'nmbs', the square of 'n', and an array of ordered strings
 */
function mean_square_sort($nmbs, $n, $strs)
{
    $aux = 0;
    for ($i = 0; $i < count($nmbs); $i++) {
        $aux = $aux + $nmbs[$i];
    }
    $mean = $aux / count($nmbs);

    $squared = square($n);

    $array_sorted = $strs;              // Clone
    sort($array_sorted);                // Sort

    $result = [$mean, $squared, $array_sorted];

    return $result;
}



/**
 * Returns the factorial of a number (the number must be integer) using recursion
 * @param {Number} x - Number that is an integer.
 * @returns {Array} res - The factorial of a number
 */
function factorial($x) {
    if ($x <= 1) {
        return 1;
    }
    $res = $x * factorial($x - 1);  // factorial is being called again
    return $res;
}



// CALLING FUNCTIONS

hello();


$x = 2;
$sqr = square($x);
echo '<p>The square of ' . $x . ' is ' . $sqr . '.</p>';


$s = sum(square(2), 3);
echo '<p>The sum of ' . square(2) . ' and ' . 3 . ' is ' . $s . '.</p>';


$p = product(4, sum(2, square(1)), true);
echo '<p>The product of ' . $p[0] . ' and ' . $p[1] . ' is ' . $p[2] . '.</p>';


$latitudes = [-2.4, 7.4, 3, 4.6, -5];
$number = sum(1, 1);
$weather = ['sunny', 'cloudy', 'windy', 'rainy'];
$res = mean_square_sort($latitudes, $number, $weather);
echo '<p>Return of the \'mean_square_sort\' function: ' . $res[0] . ' ' . $res[1] . ' ' . implode(',', $res[2]) . '.</p>';


echo '<p>The factorial of ' . $res[1] . ' is ' . factorial($res[1]) . '.</p>';

?>