<?php
//File Description: PHP Functions
 
/*
function theNameOfTheFunction () {
    execute this code
}
*/
 
 
// Basic Function Example
// Function that displays Hello
function sayHello() {
    echo "Hello ";
}
 
sayHello(); // call the function
echo "Robert <br>";
 
// Basic Function With 1 Parameter
// Function that takes a number and multiples
// it by 2
function multiplyByTwo($number) {
    $answer = $number * 2;
    echo "<b>$answer</b><br>";
}
echo "3 * 2 = ";
multiplyByTwo(3); // call our function
 
// Basic Function With 2 Parameters
// Function that takes 2 numbers and adds
// them together
function sumOfTwoNumbers($num1, $num2) {
    $sum = $num1 + $num2;
    echo "<b>$sum</b><br>";
}
 
echo "100 + 100 = ";
sumOfTwoNumbers(100, 100); // call our function
 
// Basic Function Returning A Value
// Function that returns the sum of 2 numbers
function sumOfTwoNumbers2($num1, $num2) {
    $sum = $num1 + $num2;
    return $sum;
}
 
echo "300 + 100 = ";
$result = sumOfTwoNumbers2(300,100);
echo "$result <br>";
 
// Basic Function Pass Variable by Reference
// Function that resets the value of a variable
function resetToZero(&$variable) {
    $variable = 0;
}
 
$x = 900;
resetToZero($x); // reset x to 0
echo $x;
 
// Built In PHP Function Example
// Function that returns the number of days
// for a certain month for a specific year
$days = cal_days_in_month(CAL_GREGORIAN,2,2011);
echo "<br> In Feb. of 2011 there was $days days.";
?>