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Intro to PHP

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• Structure of a PHP program
  • A PHP program consists of:

    One main program Zero or more function definitions

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• The main PHP program
  • The main PHP program:

    The main program consists of all the statements enclosed by the PHP tags The main program can be broken up into multiple PHP tagged parts: <?php $a = 4; ?> This text is outside a PHP tag. <?php print("a = " . $a . "\n"); // Uses a = 4 from above !!! ?> Output: This text is outside a PHP tag. a = 4

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• PHP functions
  • Functions:

    A function begins with the keyword function Order of processing: Function definitions will be processed first         Then the main program is executed Functions will be discussed in the next section....

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• Comments in PHP
  • The # starts a comment line

    Examples:

    <?php ... # This is a comment ... ?>

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  • You can also use Java style comments:

    <?php ... // This is a comment ... /* --------------------------- This is also a comment --------------------------- */ ?>

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• File Inclusion
  • File inclusion is a handy mechanism when you need to write a large PHP program.

  • The include command syntax:

    include 'filename';

    Effect:

    Read in the file 'filename' Replace the statement include 'filename'; with the content of the included file. Continue with the processing of the program

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  • Comment:

    Include is only used when you write large PHP programs We will not be writting large PHP programs, so you do not need to use include....