PHP, Structures and Functions, Fundamental Syntaxes

CODIFICATION

php128 apg

The PHP coding follows, as in all programming languages, some basic and fundamental rules.

To write code in PHP you need to use an editor, which, depending on your level of knowledge, you can use a simple text editor.

To run a written code, you will need to have an appropriate environment and a browser.

The environment will support the PHP language.

The browser will be, in charge of, executing the code then written.

The PHP code is always delimited by the two tags:




<?php 
// initial tag

. . . . . . . . . . .

-- The PHP code --

. . . . . . . . . . .

// final tag
?>




<?=
// is always available regardless 
// of the short_open_tag ini setting
// available since PHP 5.4.0

. . . . . . . . . . .

-- The PHP code --

. . . . . . . . . . .

// final tag
?>

DELIMITERS

The final tag is sometimes omitted by some programmers.

However, this behavior may present some undesirable risks.

In this tutorial we always use the two tags.

COMMENTS

Embedded comments are important resources for identifying parts of the code.

There are two types: SINGLE LINE and MULTIPLE LINES.

See the following example:



<?php


// This is a single-line comment

#  This is also a single-line comment

/* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

   Embedded comments are important resources
   for identifying parts of the code.

    comment . . . . . . . .
    
    . . . . . . . with . . . . . . . .
    
    . . . . . . . . . multiple . . . . . .
     
    . . . . . lines - (C language style).
    
  - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
    
?>

PHP PROGRAMMING LANGUAGE

Like all programming languages PHP basically uses INSTRUCTIONS and COMMANDS to fulfill its purpose.