PHP Programming 101

As with all programming languages PHP has different variable types such as numeric, character, string and Boolean types. Boolean variables in PHP always return either true or false, integers are whole numbers, floating points are decimal or scientifically notated and strings are a chain of characters. Sounds familiar, well they are and they are mostly standard across the various programming languages. For a more in-depth discussion on the different data types of PHP go visit the manual page.
We next discuss operators such as the assignment operator which allows you to assign values to variables allowing complex operations to be constructed into more and more functional programs.

The major notable difference with PHP against other languages with regards to variables is that PHP is more “intelligent”. In C for example, variables have to be explicitly defined as either numeric or alpha-numeric and can only be used to store that defined specific form of data. PHP like all other languages supports a lot of variable types such as integers, floating point numbers, arrays and strings but with one major difference, variables are recognized automatically based on their use and the context of their use. This makes your (programmer’s) life a whole lot easier. PHP variables are defined with a “$” symbol preceding the variable name. It should also begin with either an underscore or an alpha character.

Now, to make you a better programmer we all know the value of comments. This allows you to understand the code that you have written defining and given meaning to operations as you build them up. You start with the terminators used by PHP and end with them as well. Single line comments look like this �// comment� and Multi-line ones use the syntax /* comment comment*/. A better example would be the one below:

//comment
/* comment
Comment*/
?>

In the next post we take on the best parts of PHP which would be variables which is essential in all programming languages.

As you might have seen, all of the PHP statement ends with �;� which would be somewhat similar to Perl. The valid HTML code that was handed back to the server was :



Who are You?

My name is MacGyver.

More in the coming posts when we dig deeper as we widen our understanding of PHP.

The first post had you making a program that was equivalent to the “Hello World” program used for teaching basics of a programming language and here’s how it worked. When the script was requested by opening the web page, Apache intercepted the request and passed it onto PHP which parsed the script looking for the code in between the terminators and then doing the requested operation which was to display the text contained within the echo command. This result was given back to the server then again to the client. The output contained a valid HTML so the browser was able to understand it and execute the requested operation.

Now that you have installed the necessary web server software and tested that it works (which is included in the manual) we can now get to know the basics of PHP. For our guide we will be using HTTP combined with PHP, this allows PHP code to be embedded into regular html pages and thus simplifying the execution by simply requesting the page. PHP uses start and stop tags in the form of “?php” and “?” and below is a sample:

".. PHP Code".
?>

The following sample has PHP code embedded within HTTP:



Fan: Who are You?

//print output
Echo "My name is MacGyver";?>

Upon execution or opening the page this would give you text in the browser stating the following words. “Who are You?” “My name is MacGyver“. This would be the equivalent hello world program many books use in teaching the basics of programming.