PHP/Functions/Definition
Содержание
- 1 Accessing a Global Variable from Within a Function
- 2 A Function Requiring Two Arguments
- 3 A function that calculates sales tax
- 4 A Function to Build Query Strings
- 5 A Simple User Function
- 6 Build and then call a function
- 7 Call the function
- 8 Create a User Function
- 9 Create function from string
- 10 Creating and calling a function that accepts arguments
- 11 Declaring a Function
- 12 Declaring a Simple Function
- 13 Define constant in a function
- 14 Defining functions before or after calling them
- 15 Function printing text on a Web Page
- 16 global key word in a function
- 17 nesting functions
- 18 Using nested functions
- 19 Variables Defined Outside Functions Are Inaccessible from Within a Function by Default
Accessing a Global Variable from Within a Function
<?php
$GLOBALS["user"] = "myusername";
$GLOBALS["pass"] = "mypassword";
function validatelogin ($username, $password){
if (strcmp ($username, $GLOBALS["user"]) == 0 && strcmp ($password, $GLOBALS["pass"]) == 0){
return true;
} else {
return false;
}
}
if (validatelogin ("myusername","mypassword")){
echo "You are logged in correctly";
} else {
echo "You have an incorrect username and/or password";
}
?>
A Function Requiring Two Arguments
<html>
<head><title></title></head>
<body>
<?php
function headingWrap( $txt, $size ) {
print "<h$size>$txt</h$size>";
}
headingWrap("A", 1);
headingWrap("B",2);
headingWrap("C",3);
?>
</body>
</html>
A function that calculates sales tax
<?
$price = 4.9;
$tax = .04;
function calculate_cost($tax, $price) {
$sales_tax = $tax;
return $price + ($price * $sales_tax);
}
$total_cost = calculate_cost ($tax, $price);
$total_cost = round($total_cost, 2);
print "Total cost: ".$total_cost;
?>
A Function to Build Query Strings
<html>
<head>
<title>Using http_build_query() to Build Query Strings</title>
</head>
<body>
<?php
$q = array (
"name" => "Tom",
"interest" => "Movie",
"homepage" => "http://www.example.ru"
);
$query = http_build_query( $q );
print $query;
?>
<p>
<a href="anotherpage.php?<?php print $query ?>">Go!</a>
</p>
</body>
</html>
A Simple User Function
function foo( ) {
return 1;
}
print foo( );
Build and then call a function
<?php
function helloworld (){
echo "Hello World!<br />";
}
helloworld();
function saysomething ($something){
echo $something . "<br />";
}
Saysomething ("Hello World!"); //This would output "Hello World!"
function addvalues ($firstvalue, $secondvalue){
return $firstvalue + $secondvalue;
}
$newvalue = addvalues (1,3);
echo $newvalue;
?>
Call the function
<?php
function hi( ){
echo ("Hello from function-land!");
}
hi( );
?>
Create a User Function
<html>
<head>
<title>Create a User Function</title>
<?php
function myFunction($company) {
print("<p>Welcome to $company</p>");
}
?>
</head>
<body>
<h3>Start</h3>
<?php
$company = "A";
myFunction($company);
?>
Create function from string
<?
$lambda =create_function("$a,$b","return(strlen($a)-strlen($b));");
$array = array("really long string here,boy", "this", "middling length",
"larger");
usort($array,$lambda);
print_r($array);
?>
Creating and calling a function that accepts arguments
<?
function saysomething ($something){
echo $something . "<br />";
}
Saysomething ("Hello World!");
?>
Declaring a Function
<html>
<head>
<title>Declaring a Function</title>
</head>
<body>
<?php
function bighello(){
print "<h1>HELLO!</h1>";
}
bighello();
?>
</body>
</html>
Declaring a Simple Function
<?php
function aFunction(){
print "Music is a way of life!";
}
aFunction();
?>
Define constant in a function
<?php
define("CONST1", 1);
function MyTest() {
define("CONST2", 2);
}
MyTest();
echo "CONST1 = " . CONST1 . " and CONST2 = " . CONST2 . "\n";
?>
Defining functions before or after calling them
<?
function page_header() {
print "<html><head><title>Welcome to my site</title></head>";
print "<body bgcolor="#ffffff">";
}
page_header();
print "Welcome, $user";
page_footer();
function page_footer() {
print "<hr>Thanks for visiting.";
print "</body></html>";
}
?>
Function printing text on a Web Page
<HTML>
<HEAD>
<TITLE> Printing text on a Web Page </TITLE>
</HEAD>
<BODY>
<?php
function textonweb ($content, $fontsize) {
echo "<FONT SIZE=$fontsize>$content</FONT>";
}
textonweb ("A <BR>", 7);
textonweb ("AA. <BR>", 3);
textonweb ("AAA. <BR>", 3);
textonweb ("AAAA! <BR>", 3);
?>
</BODY>
</HTML>
global key word in a function
<?php
$a = 7;
function test() {
global $a;
$a = 20;
}
test();
echo "\$a = $a\n";
?>
nesting functions
<?php
function myFunction($price,$tax) {
function convert_pound($dollars, $conversion=1.6) {
return $dollars * $conversion;
}
$total = $price + ($price * $tax);
echo "Total cost in dollars: $total. Cost in British pounds: " . convert_pound($total);
}
myFunction(15.00,.075);
echo convert_pound(15);
?>
Using nested functions
<?
function display_footer($site_name) {
function display_copyright($site_name) {
print "© ". date("Y"). " $site_name.";
}
print "contact us<br>";
display_copyright($site_name);
}
$site_name = "PHP";
display_footer($site_name);
?>
Variables Defined Outside Functions Are Inaccessible from Within a Function by Default
<html>
<head>
<title>No Default Access to Globals in Functions</title>
</head>
<body>
<div>
<?php
$life = 42;
function meaningOfLife() {
print "The meaning of life is $life<br />";
}
meaningOfLife();
?>
</div>
</body>
</html>