Skip to main content

Introduction to PHP Part III

Please read the post Introduction to PHP, How to Insert Dynamic Content on WebPages, if you haven’t already.

Below is the code snippet from the previous post.


  <html>
  <body>
  Date: <?php echo date("H:i A, jS F Y"); ?>
  </body>
  </html>

I’d like to state the following regarding the above code:

  1. PHP code starts with a <?php and ends with a ?> tag. Though PHP supports some other tags (depending on the configuration) which signify the same but these are the most widely used and are guaranteed to work on most servers.

  2. You can have any number of <?php …?> blocks in a file.

  3. In PHP too, like C++ comments are written using // (single line) and /*…*/ (multi-line) symbols. Besides these one more symbol i.e. ‘#’ symbol can also be used for single line comments.

  4. [Update: Added this point] Each statement of PHP ends with a semicolon ";" just like in C++. [/Update]

  5. No need to bother about the arguments passed to the date() function now, it is just a format string which tells the date function which format to return the date in. eg. “H:i A, jS F Y” tells the date function to return date and time as “06:00 AM, 18th April 2008”. Echo command just echoes (prints) it to the screen.

  6. Files containing PHP codes must have a “.php” extension (default) even if it contains HTML too.

  7. Any file having an extension “.php” is parsed by PHP. As someone requests a PHP page, the server hands it over to PHP parser. PHP parses the file returning HTML codes as it is, but when it finds a <?php…?> block, it interprets the code between the tags and returns the result back. So we get something like this upon parsing the PHP code at the top of this post:

    
      <html>
      <body>
      Date: 06:00 AM, 18th April 2008
      </body>
      </html>
    
    

    In this case, line 1 and 2 were returned as is without any interpretation whereas the PHP code between <?php…?> were interpreted and results were returned. Again line 4 and 5 were returned the same.

Related Articles:

Popular posts from this blog

Fix For Toshiba Satellite "RTC Battery is Low" Error (with Pictures)

RTC Battery is Low Error on a Toshiba Satellite laptop "RTC Battery is Low..." An error message flashing while you try to boot your laptop is enough to panic many people. But worry not! "RTC Battery" stands for Real-Time Clock battery which almost all laptops and PCs have on their motherboard to power the clock and sometimes to also keep the CMOS settings from getting erased while the system is switched off.  It is not uncommon for these batteries to last for years before requiring a replacement as the clock consumes very less power. And contrary to what some people tell you - they are not rechargeable or getting charged while your computer or laptop is running. In this article, we'll learn everything about RTC batteries and how to fix the error on your Toshiba Satellite laptop. What is an RTC Battery? RTC or CMOS batteries are small coin-shaped lithium batteries with a 3-volts output. Most laptops use

The Best Way(s) to Comment out PHP/HTML Code

PHP supports various styles of comments. Please check the following example: <?php // Single line comment code (); # Single line Comment code2 (); /* Multi Line comment code(); The code inside doesn't run */ // /* This doesn NOT start a multi-line comment block /* Multi line comment block The following line still ends the multi-line comment block //*/ The " # " comment style, though, is rarely used. Do note, in the example, that anything (even a multi-block comment /* ) after a " // " or " # " is a comment, and /* */ around any single-line comment overrides it. This information will come in handy when we learn about some neat tricks next. Comment out PHP Code Blocks Check the following code <?php //* Toggle line if ( 1 ) {      // } else {      // } //*/ //* Toggle line if ( 2 ) {      // } else {      // } //*/ Now see how easy it is to toggle a part of PHP code by just removing or adding a single " / " from th

Introduction to Operator Overloading in C++

a1 = a2 + a3; The above operation is valid, as you know if a1, a2 and a3 are instances of in-built Data Types . But what if those are, say objects of a Class ; is the operation valid? Yes, it is, if you overload the ‘+’ Operator in the class, to which a1, a2 and a3 belong. Operator overloading is used to give special meaning to the commonly used operators (such as +, -, * etc.) with respect to a class. By overloading operators, we can control or define how an operator should operate on data with respect to a class. Operators are overloaded in C++ by creating operator functions either as a member or a s a Friend Function of a class. Since creating member operator functions are easier, we’ll be using that method in this article. As I said operator functions are declared using the following general form: ret-type operator#(arg-list); and then defining it as a normal member function. Here, ret-type is commonly the name of the class itself as the ope