PHP Functions - Returning Values | Lombok Study

Besides being able to pass functions information, you can also have them return a value. However, a function can only return one thing, although that thing can be any integer, float, array, string, etc. that you choose!
How does it return a value though? Well, when the function is used and finishes executing, it sort of changes from being a function name into being a value. To capture this value you can set a variable equal to the function. Something like:
   * $myVar = somefunction();
Let's demonstrate this returning of a value by using a simple function that returns the sum of two integers.

PHP Code:

<?php
function mySum($numX, $numY){
$total = $numX + $numY;
return $total;
}
$myNumber = 0;
echo "Before the function, myNumber = ". $myNumber ."<br />";
$myNumber = mySum(3, 4); // Store the result of mySum in $myNumber
echo "After the function, myNumber = " . $myNumber ."<br />";
?>

Display:
Before the function, myNumber = 0
After the function, myNumber = 7

When we first print out the value of $myNumber it is still set to the original value of 0. However, when we set $myNumber equal to the function mySum, $myNumber is set equal to mySum's result. In this case, the result was 3 + 4 = 7, which was successfully stored into $myNumber and displayed in the second echo statement!

PHP Functions With Parameters | Lombok Study

Another useful thing about functions is that you can send them information that the function can then use. Our first function myCompanyMotto isn't all that useful because all it does, and ever will do, is print out a single, unchanging string.
However, if we were to use parameters, then we would be able to add some extra functionality! A parameter appears with the parentheses "( )" and looks just like a normal PHP variable. Let's create a new function that creates a custom greeting based off of a person's name.
Our parameter will be the person's name and our function will concatenate this name onto a greeting string. Here's what the code would look like.

PHP Code with Function:

<?php
function myGreeting($firstName){
echo "Hello there ". $firstName . "!<br />";
}
?>

When we use our myGreeting function we have to send it a string containing someone's name, otherwise it will break. When you add parameters, you also add more responsibility to you, the programmer! Let's call our new function a few times with some common first names.

PHP Code:

<?php
function myGreeting($firstName){
echo "Hello there ". $firstName . "!<br />";
}
myGreeting("Jack");
myGreeting("Ahmed");
myGreeting("Julie");
myGreeting("Charles");
?>

Display:
Hello there Jack!
Hello there Ahmed!
Hello there Julie!
Hello there Charles!

It is also possible to have multiple parameters in a function. To separate multiple parameters PHP uses a comma ",". Let's modify our function to also include last names.

PHP Code:

<?php
function myGreeting($firstName, $lastName){
echo "Hello there ". $firstName ." ". $lastName ."!<br />";
}
myGreeting("Jack", "Black");
myGreeting("Ahmed", "Zewail");
myGreeting("Julie", "Roberts");
myGreeting("Charles", "Schwab");
?>

Display:
Hello there Jack Black!
Hello there Ahmed Zewail!
Hello there Julie Roberts!
Hello there Charles Schwab!

Comments PHP | Lombok Study

Single Line Comment
While there is only one type of comment in HTML, PHP has two types. The first type we will discuss is the single line comment. The single line comment tells the interpreter to ignore everything that occurs on that line to the right of the comment. To do a single line comment type "//" or "#" and all text to the right will be ignored by PHP interpreter.

PHP Code :

<?php
echo "Hello World!"; // This will print out Hello World!
echo "<br />Psst...You can't see my PHP comments!"; // echo "nothing";
// echo "My name is Humperdinkle!";
# echo "I don't do anything either";
?>

Display :
Hello World!

You can't see my PHP comments!
Notice that a couple of our echo statements were not evaluated because we commented them out with the single line comment. This type of line commenting is often used for quick notes about complex and confusing code or to temporarily remove a line of PHP code.

Multiple Line Comment
Similiar to the HTML comment, the multi-line PHP comment can be used to comment out large blocks of code or writing multiple line comments. The multiple line PHP comment begins with " /* " and ends with " */ ".

PHP Code :
<?php
/* This Echo statement will print out my message to the
the place in which I reside on. In other words, the World. */
echo "Hello World!";
/* echo "My name is Humperdinkle!";
echo "No way! My name is Uber PHP Programmer!";
*/
?>

Display :
Hello World!

Switch PHP | Lombok Study

In our example the single variable will be $destination and the cases will be: Las Vegas, Amsterdam, Egypt, Tokyo, and the Caribbean Islands.
PHP Code : 
$destination = "Tokyo";
echo "Traveling to $destination";
switch ($destination){
    case "Las Vegas":
       echo "Bring an extra $500";
   break;
   case "Amsterdam":
       echo "Bring an open mind";
   break;
   case "Egypt":
       echo "Bring 15 bottles of SPF 50 Sunscreen";
   break;
   case "Tokyo":
       echo "Bring lots of money";
   break;
   case "Caribbean Islands":
       echo "Bring a swimsuit";
   break;
}

Display :
Traveling to Tokyo
Bring lots of money

The value of $destination was Tokyo, so when PHP performed the switch operating on $destination in immediately did a search for a case with the value of "Tokyo". It found it and proceeded to execute the code that existed within that segment.

You might have noticed how each case contains a break; at the end of its code area. This break prevents the other cases from being executed. If the above example did not have any break statements then all the cases that follow Tokyo would have been executed as well. Use this knowledge to enhance the power of your switch statements!

The form of the switch statement is rather unique, so spend some time reviewing it before moving on. Note: Beginning programmers should always include the break; to avoid any unnecessary confusion.

Include VS Require PHP | Lombok Study

Use Include :
When you include a file with the include command and PHP cannot find it you will see an error message like the following :

PHP Code Include:

<?php
include("noFileExistsHere.php");
echo "Hello World!";
?>

Display:
Warning: main(noFileExistsHere.php): failed to open stream: No such file or directory in /home/websiteName/FolderName/tizagScript.php on line 2 Warning: main(): Failed opening 'noFileExistsHere.php' for inclusion (include_path='.:/usr/lib/php:/usr/local/lib/php') in /home/websiteName/FolderName/tizagScript.php on line 2

Hello World!

Use Require :
Notice that our echo statement is still executed, this is because a Warning does not prevent our PHP script from running. On the other hand, if we did the same example but used the require statement we would get something like the following example.

PHP Code Require:

<?php

require("noFileExistsHere.php");

echo "Hello World!";

?>

Display:
Warning: main(noFileExistsHere.php): failed to open stream: No such file or directory in /home/websiteName/FolderName/tizagScript.php on line 2
Fatal error: main(): Failed opening required 'noFileExistsHere.php' (include_path='.:/usr/lib/php:/usr/local/lib/php') in /home/websiteName/FolderName/tizagScript.php on line 2

The echo statement was not executed because our script execution died after the require command returned a fatal error! We recommend that you use require instead of include because your scripts should not be executing if necessary files are missing or misnamed.

E-Mail With PHP | Lombok Study

The Mail Command
Mail is extremely easy to send from PHP, unlike using scripting languages which require special setup (like CGI). There is actually just one command, mail() for sending mail. It is used as follows:

mail($to,$subject,$body,$headers);

In this example I have used variables as they have descriptive names but you could also just place text in the mail command. Firstly, $to. This variable (or section of the command) contains the e-mail address to which the mail will be sent. $subject is the section for the subject of the e-mail and $body is the actual text of the e-mail.

The section $headers is used for any additional e-mail headers you may want to add. The most common use of this is for the From field of an e-mai but you can also include other headers like cc and bcc.
Sending An E-mail
Before sending your mail, if you are using variables, you must, of course, set up the variable content beforehand. Here is some simple code for sending a message:

$to = "php@gowansnet.com";
$subject = "PHP Is Great";
$body = "PHP is one of the best scripting languages around";
$headers = "From: webmaster@gowansnet.com\n";
mail($to,$subject,$body,$headers);
echo "Mail sent to $to";

This code will acutally do two things. Firstly it will send a message to php@gowansnet.com with the subject 'PHP Is Great' and the text:

PHP is one of the best scripting languages around

and the e-mail will be from webmaster@gowansnet.com. It will also output the text:

Mail sent to php@gowansnet.com

to the browser.

Formatting E-mail
Something you may have noticed from the example is that the From line ended with \n. This is acutally a very important character when sending e-mail. It is the new line character and tells PHP to take a new line in an e-mail. It is very important that this is put in after each header you add so that your e-mail will follow the international standards and will be delivered.

The \n code can also be used in the body section of the e-mail to put line breaks in but should not be used in the subject or the To field.

Mail Without Variables
The e-mail above could have been sent using different variable names (it is the position of the variables in relation to the commas, not the name of them which decides on their use). It could also have been done on one line using text like this:

mail("php@gowansnet.com","PHP Is Great","PHP is one of the best scripting languages around","From: webmaster@gowansnet.com\n");

But that would make your code slightly harder to read.

Error Control
As anyone who has been scripting for a while will know, it is extremely easy to make mistakes in your code and it is also very easy to input an invalid e-mail address (especially if you are using your script for form to mail). Because of this, you can add in a small piece of code which will check if the e-mail is sent:

if(mail($to,$subject,$body,$headers)) {
echo "An e-mail was sent to $to with the subject: $subject";
} else {
echo "There was a problem sending the mail. Check your code and make sure that the e-mail address $to is valid";
}

This code is quite self explanitory. If the mail is sent successfully it will output a message to the browser telling the user, if not, it will display an error message with some suggestions for correcting the problem.

Array PHP | Lombok Study

Arrays are common to many programing languages. They are special variables which can hold more than one value, each stored in its own numbered 'space' in the array. Arrays are extremely useful, especially when using WHILE loops.

Setting Up An Array

Setting up an array is slightly different to setting up a normal variable. In this example I will set up an array with 5 names in it :

$names[0] = 'John';
$names[1] = 'Paul';
$names[2] = 'Steven';
$names[3] = 'George';
$names[4] = 'David';

As you can see, the parts of an array are all numbered, starting from 0. To add a value to an array you must specify the location in the array by putting a number in [ ].

Reading From An Array

Reading from an array is just the same as putting information in. All you have to do is to refer to the array and the number of the piece of data in the array. So if I wanted to print out the third name I could use the code:

echo "The third name is $names[2]";

Which would output:
The third name is Steven

Using Arrays And Loops
One of the best uses of a loop is to output the information in an array. For instance if I wanted to print out the following list of names:

Name 1 is John
Name 2 is Paul
Name 3 is Steven
Name 4 is George
Name 5 is David

I could use the following code:

$number = 5;
$x = 0;
while ($x < $number) {
$namenumber = $x + 1;
echo "Name $namenumber is $names[$x]<br>";
++$x;
}

As you can see, I can use the variable $x from my loop to print out the names in the array. You may have noticed I am also using the variable $namenumber which is always 1 greater than $x. This is because the array numbering starts from 0, so to number the names correctly in the output I must add one to the actual value.

The While Loop PHP | Lombok Study

The WHILE loop is one of the most useful commands in PHP. It is also quite easy to set up and use. A WHILE loop will, as the name suggests, execute a piece of code until a certain condition is met.
Repeating A Set Number Of Times

If you have a piece of code which you want to repeat several times without retyping it, you can use a while loop. For instance if you wanted to print out the words "Hello World" 5 times you could use the following code:

$times = 5;

$x = 0;

while ($x < $times) { 

echo "Hello World"; 

++$x; 

} 

I will now explain this code. The first two lines are just setting the variables. The $times variable holds the number of times you want to repeat the code. The $x variable is the one which will count the number of times the code has been executed. After these is the WHILE line. This tells the computer to repeat the code while $i is less than $times (or to repeat it until $i is equal to $times). This is followed by the code to be executed which is enclosed in { }.

After the echo line which prints out the text, there is another very important line:

++$x; 

What this does is exactly the same as writing:

 $x = $x + 1; 

It adds one to the value of $x. This code is then repeated (as $x now equals 1). It continues being repeated until $x equals 5 (the value of times) when the computer will then move on to the next part of the code.

Using $x 

The variable counting the number of repeats ($x in the above example) can be used for much more than just counting. For example if you wanted to create a web page with all the numbers from 1 to 1000 on it, you could either type out every single one or you could use the following code:

$number = 1000;

$current = 0;

while ($current < $number)

{ ++$current; echo "$current";

}

There are a few things to notice about this code. Firstly, you will notice that I have placed the ++$current; before the echo statement. This is because, if I didn't do this it would start printing numbers from 0, which is not what we want. The ++$current; line can be placed anywhere in your WHILE loop, it does not matter. It can, of course, add, subtract, multiply, divide or do anthing else to the number as well.

The other reason for this is that, if the ++$current; line was after the echo line, the loop would also stop when the number showed 999 because it would check $current which would equal 1000 (set in the last loop) and would stop, even though 1000 had not yet been printed.

IF Statements PHP | Lombok Study

The Basics Of IF
If statements are used to compare two values and carry out different actions based on the results of the test. If statements take the form IF, THEN, ELSE. Basically the IF part checks for a condition. If it is true, the then statement is executed. If not, the else statement is executed.

IF Strucure
The structure of an IF statement is as follows:

IF (something == something else)

{

THEN Statement

} else {

ELSE Statement

}

IF in Variables
The most common use of an IF statement is to compare a variable to another piece of text, a number, or another variable. For example:

if ($username == "webmaster")

which would compare the contents of the variable to the text string. The THEN section of code will only be executed if the variable is exactly the same as the contents of the quotation marks so if the variable contained 'Webmaster' or 'WEBMASTER' it will be false.

Constructing The THEN Statment
To add to your script, you can now add a THEN statement:

if ($username == "webmaster") {

echo "Please enter your password below";

}

This will only display this text if the username is webmaster. If not, nothing will be displayed. You can actually leave an IF statement like this, as there is no actual requirement to have an ELSE part. This is especially useful if you are using multiple IF statements.

Constructing The ELSE Statement
Adding The ELSE statement is as easy as the THEN statement. Just add some extra code:

if ($username == "webmaster") {

echo "Please enter your password below";

} else {

echo "We are sorry but you are not a recognised user";

}

Of course, you are not limited to just one line of code. You can add any PHP commands in between the curly brackets. You can even include other IF statments (nested statements).

Other Comparisons
There are other ways you can use your IF statement to compare values. Firstly, you can compare two different variables to see if their values match e.g.

if ($enteredpass == $password)

You can also use the standard comparision symbols to check to see if one variable is greater than or less than another:

if ($age < "13") Or : if ($date > $finished)

You can also check for multiple tests in one IF statement. For instance, if you have a form and you want to check if any of the fields were left blank you could use:

if ($name == "" || $email == "" || $password == "") {

echo "Please fill in all the fields";

}

Make Variabel PHP | Lombok Study

As with other programming languages, PHP allows you to define variables. In PHP there are several variable types, but the most common is called a String. It can hold text and numbers. All strings begin with a $ sign. To assign some text to a string you would use the following code:

$welcome_text = "Hello and welcome to my website.";

This is quite a simple line to understand, everything inside the quotation marks will be assigned to the string. You must remember a few rules about strings though:

Strings are case sensetive so $Welcome_Text is not the same as $welcome_text
String names can contain letters, numbers and underscores but cannot begin with a number or underscore
When assigning numbers to strings you do not need to include the quotes so:

$user_id = 987

would be allowed.

Outputting Variables

To display a variable on the screen uses exactly the same code as to display text but in a slightly different form. The following code would display your welcome text:

$welcome_text = "Hello and welcome to my website.";

print($welcome_text);

?>

As you can see, the only major difference is that you do not need the quotation marks if you are printing a variable.

Printing Text PHP | Lombok Study

To output text in your PHP script is actually very simple. As with most other things in PHP, you can do it in a variety of different ways. The main one you will be using, though, is print. Print will allow you to output text, variables or a combination of the two so that they display on the screen.

The print statement is used in the following way:

print("Hello world!");

I will explain the above line :
print is the command and tells the script what to do. This is followed by the information to be printed, which is contained in the brackets. Because you are outputting text, the text is also enclosed instide quotation marks. Finally, as with nearly every line in a PHP script, it must end in a semicolon. You would, of course, have to enclose this in your standard PHP tags, making the following code:

Which will display:

Hello world!

PHP Database Connection

PHP can connect to MySQL because it is a useful PHP module for it. Librarinya own module or file I do not know its contents, which is important we use that the library, in windows, library’s name is php_mysql.dll.

That the library consists of functions related to the MySQL databse connection, like mysql_connect (), mysql_select_db (), mysql_query (), mysql_fetch_row (), mysql_fetch_array () etc.. If the module is the rename or delete, then PHP can not communicate with MySQL.

If MySQL is on a local server, (in other words, there are on your own website), then the hostname used was localhost

sintax means that you use is:

mysql_connect ("localhost", "mysql_username_you_use", "password_from_username");

1. PHP & MySQL Connection
<?php

$ Hostmysql = "localhost";

$ Username = "mysqlusername";

$ Password = "mysqlpassword";

$ Database = "databasename";

$ Conn = mysql_connect ("$ hostmysql", "$ username", "$ password");

if (! $ conn) die ("Connection failed");

mysql_select_db ($ database, $ conn) or die ("Database not found");

?>

The explanation:

1.       mysql_connect

used to make the connection from PHP to MySQL server. Data on the hostname, MySQL username, and password that is used has been represented by the variable $ hostmysql, $ username, $ password. Writing will be equal to:

mysql_connect ("localhost", "username", "password");

2.       mysql_select_db

to select the database to be used.

3.       if (! $ conn) die ("Connection failed");

if the connection failed to be created (! $ conn), it will display an error message

for more details go to http://php.net/manual/en/function.mysql-connect.php

Tip :     Any operation related PHP with MySQL, would need a syntax like the above. for easier,

better saved first by the name db_config.php. If the syntax is needed again, then we do include the file db_config.php it.

2. Creating Tables in MySQL

<?php

include ("db_config.php");

mysql_query ("CREATE TABLE users (firstname VARCHAR (20), lastname VARCHAR (20), city VARCHAR (20 ))");

?>

The explanation:

1.       include ("db-config.php");

include command is used to include a file (in the example above is the db-config.php file).

2.       mysql_query

general format of this command is mysql_query (string query).

mysql_query will often be found in this article.

3. Entering data in the table

<?php

include ("db-config.php");

$ Insert = "INSERT INTO users (firstname, lastname, city) VALUES ('I', 'Own', 'Indonesia')";

mysql_query ($ insert) or die ("can not enter data into the table");

?>

4. Displaying data from a table

<?php

include ("db_config.php");

$ Query = "SELECT * FROM user";

$ Result = mysql_query ($ query);

$ Numrows = mysql_num_rows ($ result);

while ($ row = mysql_fetch_array ($ result))

{

echo "Number of data: $ numrows";

echo "Name: $ row [firstname]";

echo "Last Name: $ row [lastname]";

echo "City: $ row [city]";

}

?>

The explanation:

1.       mysql_num_rows

used to calculate the number of lines drawn from the results of execution query (mysql_query).

2.       while () {}

used for looping over the desired data is still there. (In the example above: will display all the contents of the table).

3.       mysql_fetch_array

display data from a table in the form of arrays

For any other use (delete, update, etc.) that change only query strings only.

Session in PHP

PHP has a session (note the activity) that is used to maintain /maintaining access information from an accessor / user web application. Session allows the user access tracking, application usage by pangaturan users and improve the website services.

Each visitor will be given a unique id, called a session id (Session_id). This ID can be stored in a cookie on the user side or is included in the URL.

Session connection between the client and the server will be lost or broken if the browser closed. If the browser is run back and do the connection to the server considered a new connection. The functions of the session:

1. session_start (), to start the session.

2. session_destroy (), to end the session.

3. session_id (), to retrieve or determine the identity of a session (session id).

4. session_register (), to register into a session variable.

OOP (Object Oriented Programing) Within the scope of OOP PHP is not so complete, in this discussion we will discuss about the use of class and function only. 

Example:

Database class

{

var $ host = "localhost";

var $ user = "root";

var $ pass = "1";

var $ db = "Siji";

var $ linkid;

var $ query;

var $ result;

var $ array;

    function connection ()
    {
        $ This-> linkid = @ mysql_connect ($ this-> host, $ this-> user, $ this-> pass);
        if (! $ this-> linkid)
        {
             $ This-> error = "connection failed". Mysql_error ()."< br> ";
             return false;
        }
        mysql_select_db ($ this-> db);
        return $ this-> linkid;
    }
    
    function query ($ strqry)
    {
        $ This-> result = @ mysql_query ($ strqry);
        if (! $ this-> result)
        {
            $ This-> error = "query failed to run". Mysql_error ()."< br> ". $ Strqry;
            return false;
        }
        
        return $ this-> result;
    }
        
    farray function ()
    {
    $ This-> array = mysql_fetch_array ($ this-> result); return $ this-> array;
    } } 

Example usage:
<?

require ("koneksi.php");

$ Db = new database ();

$ Db-> connection ();

$ Db-> query ("select * from MHS");

while ($ data = $ db-> farray ()) {

echo $ data ['name']."< br /> ";

}

?>

History of PHP Language

PHP originally stood for personal home page. Its development began in 1994 when the Danish/Greenlandic programmer Rasmus Lerdorf initially created a set of Perl scripts he called 'Personal Home Page Tools' to maintain his personal homepage, including tasks such as displaying his résumé and recording how much traffic his page was receiving.

He rewrote these scripts as C programming language Common Gateway Interface (CGI) binaries, extending them to add the ability to work with web forms and to communicate with databases and called this implementation 'Personal Home Page/Forms Interpreter' or PHP/FI. PHP/FI could be used to build simple, dynamic web applications. Lerdorf released PHP/FI as 'Personal Home Page Tools (PHP Tools) version 1.0' publicly on June 8, 1995, to accelerate bug location and improve the code. This release already had the basic functionality that PHP has today. This included Perl-like variables, form handling, and the ability to embed HTML. The syntax was similar to Perl but was more limited and simpler, although less consistent. A development team began to form and, after months of work and beta testing, officially released PHP/FI 2 in November 1997.

Zeev Suraski and Andi Gutmans, two Israeli developers at the Technion IIT, rewrote the parser in 1997 and formed the base of PHP 3, changing the language's name to the recursive initialism PHP: Hypertext Preprocessor. Afterwards, public testing of PHP 3 began, and the official launch came in June 1998. Suraski and Gutmans then started a new rewrite of PHP's core, producing the Zend Engine in 1999. They also founded Zend Technologies in Ramat Gan, Israel.

On May 22, 2000, PHP 4, powered by the Zend Engine 1.0, was released. As of August 2008 this branch is up to version 4.4.9. PHP 4 is no longer under development nor will any security updates be released.

On July 13, 2004, PHP 5 was released, powered by the new Zend Engine II. PHP 5 included new features such as improved support for object-oriented programming, the PHP Data Objects (PDO) extension (which defines a lightweight and consistent interface for accessing databases), and numerous performance enhancements. In 2008 PHP 5 became the only stable version under development. Late static binding had been missing from PHP and was added in version 5.3.

A new major version has been under development alongside PHP 5 for several years. This version was originally planned to be released as PHP 6 as a result of its significant changes, which included plans for full Unicode support. However, Unicode support took developers much longer to implement than originally thought, and the decision was made in March 2010 to move the project to a branch, with features still under development moved to trunk.

Changes in the new code include the removal of register_globals, magic quotes, and safe mode. The reason for the removals was that register_globals had given way to security holes, and the use of magic quotes had an unpredictable nature, and was best avoided. Instead, to escape characters, magic quotes may be replaced with the addslashes() function, or more appropriately an escape mechanism specific to the database vendor itself like mysql_real_escape_string() for MySQL. Functions that will be removed in future versions and have been deprecated in PHP 5.3 will produce a warning if used.

Many high-profile open-source projects ceased to support PHP 4 in new code as of February 5, 2008, because of the GoPHP5 initiative, provided by a consortium of PHP developers promoting the transition from PHP 4 to PHP 5.

PHP currently does not have native support for Unicode or multibyte strings; Unicode support is under development for a future version of PHP and will allow strings as well as class, method, and function names to contain non-ASCII characters.

PHP interpreters are available on both 32-bit and 64-bit operating systems, but on Microsoft Windows the only official distribution is a 32-bit implementation, requiring Windows 32-bit compatibility mode while using Internet Information Services (IIS) on a 64-bit Windows platform. As of PHP 5.3.0, experimental 64-bit versions are available for MS Windows.

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