What Is PHP?

The full form of PHP is Hypertext PreProcessor and is a server-side scripting language. The PHP code can be combined with regular HTML tags and parsed on the server. The creator of PHP, Rasmus Lerdorf first displayed the language in the form of a Perl script . In 1997 it was adapted by Andi Gutmans and Zeev Suraski to use a C-written compiler. They completely reconstructed the original PHP into the web language that we know and use today.

Uses of PHP

It is used in the creation of dynamic web pages. Web developers like it because of its fast parsing and flexibility and versatility. PHP is a popular tool for managing a form's data after it is submitted and comes built in with many different interfaces and API's. It has database capability built into the language, the most common database being MySQL. Typically the PHP can connect to any SQL enabled database.

The Syntax of PHP is similar in structure to Perl and C where curly braces { } define blocks of code and semi-colons specify the end of a statement PHP is as easy to learn as Perl. It maintains all the traditional loops, if/else, and subroutines that are expected in a programming language. One difference between the two is that the code'?' is embedded in with the HTML; you could however, use a separate file. The PHP code is different from HTML code by use of the opening and closing tags. When it finds a PHP file, it tells the server to scan through for these tags, and execute the code in between them. The server recognizes a PHP enabled file by its extension, .php. These are essentially HTML files with PHP codes in them.

Getting Started

To start PHP requires a server with PHP installed and a simple ASCII text editor such as Notepad or VI, eMacs, Kate, etc. for a UNIX/Linux machine.

What are the problems faced by PHP?

It is case sensitive. For example if you name a variable $MyVar, you cannot call it as $myvar or $mYvAr. In case you forget to close your curly brackets, then it helps to indent lines inside the curly braces so that any missing braces can be spotted easily.

Ten years ago you could include a hit counter on your website and announce proudly that your site was doing "very well" as soon as the number reached 100,000. The current process is not nearly as simple or straightforward. The internet works in complicated ways that have evolved to solve a number of small problems. Consequently, concrete statistics are often difficult to obtain. If you believe the number of online visitors is a reliable indicator to gauge the popularity of your site or the potential sales of your product, you should consider the following:

1. Hit - Every time a user requests a file on your site (a page, not a picture or link to another site) it counts as a hit.

2. File - When a file or page is actually sent to the user, it counts as a file. Files normally outnumber hits, but neither is very useful in measuring traffic. Any IP can request all of the files on your page several times in one hour without any actual involvement from the user.

3. Impressions - This is a concept that has existed in advertising for many decades. For example, a 2-page magazine advertisement counts as one "showing of a creative concept". This equates to one impression every time a reader sees it. If your web page contains five small banners, you could have 10,000 page views, but 50,000 impressions.

4. Page Views - Almost everyone believe this is the most important traffic statistic. This term simply refers to the number of times any particular page has been viewed. This metric can be useful. However, values can often be over-inflated and should always be considered in conjunction with unique visits.

5. Visits & Unique Visits - A visit is simply logged every time a remote IP requests one of your pages for the first time in a timeout period. A unique visit is usually defined as "one visit per IP per day", regardless of timeouts.

The above are all very important metrics, but understanding them properly is key. The best way to decide how your site's traffic is performing is by creating a formula. If you know what you are doing, you can develop your own formula. However, there are plenty of effective formulas currently available. A basic idea of how to evaluate your traffic involves reviewing monthly averages, unique visits and page views. This will give you an idea regarding how many individuals visit your site, how many pages they view, and how long they remain.

A basic formula from MarketingExperiments.com would be:

C = 4M + 3V + 2(I-F) - 2A

This formula shows that conversions are a product of motivation (M), value (V) and then the friction (F) elements minus the incentives (I). This will help you determine how many customers are likely to purchase your product. However, you need all the values first! You can purchase online analytic tools or download them for an upfront or monthly fee. All of them can return useful data to a webmaster.

If you are not an expert webmaster, or you do not understand many of the technical intricacies of web traffic, you should download Google Analytics. This is one of Google's new free products, and all you require is a GMail account and a web site. The program provides easy to read analytic data in a web-based form for your website. This can make it easy to determine which metrics would be most useful for analyzing your online traffic.

Michael Ehlert
RevUpYourWebBusiness.com

BETA is a pure object oriented programming language developed by Scandinavian School in System Development, Nordic Universities.

This was released after a series of enhancements of their first object oriented language SimulaI which was a simulation language. Soon it was generalized into Simula67 which had the object oriented framework, and worked on the concepts of class, sub-class, virtual functions etc. This was enhanced by another object oriented language Delta that worked for system description; this meant it could express predicate logic and state changes. This was a non-executable effort and thus did not qualify as a language. So it was decided to design a programming language Gamma that works as Delta but is executable.

Eventually, Gamma was never made, rather Beta was made. While Beta was being made, it was realized that Beta was much more powerful than what Gamma would be or ever could be. Beta is a programming language like C++.

Currently, BETA is available on UNIX workstations, on PowerPC Macintosh and on Intel-based PCs. BETA has an optimum balance between compile time checking and run time checking. The type cast checking is done at compile time, however, for the entire set of type check and type conversion to be done at compile time requires a lot of time and thus increases the complexity of a program. Thus, an optimum balance has been made.

BETA is a logical description of the language. It works on the concepts of class, sub-class, virtual functions etc. It also contains transient variables, ones whose scope is program execution, and persistent variables, those whose values are retained in the disk space and are available at the time of next execution.