How to construct a class diagram?

What do the terms class diagram and architecture diagram mean? How do you create one for a project using PHP?

• I have participated in a coding competition in which I am supposed to create a 'Virtual Library.' In our first submission we are supposed to submit the high-level specifications of our web application. Along with that, we are supposed to submit an architecture diagram and a class diagram. What are class diagrams and architecture diagrams? I am planning to develop the application using PHP. I tried searching on Google but did not get a clear definition for architecture, and the class digram examples involved concepts like class, method, attributes etc. which do not apply to PHP. How should I design these two diagrams for a project that will use PHP?

• Answer:

  Example of application architecture diagram: Example of application's class diagram: As Anand pointed out in the comment, you should update your PHP knowledge, because OO is supported since a long ago. You can get a look here: http://net.tutsplus.com/tutorials/php/object-oriented-php-for-beginners/