JAWAHARLAL NEHRU TECHNOLOGICAL UNIVERSITY HYDERABAD MCA 2020 WEB TECHNOLOGIES Previous Question Paper (October/ November - 2020 - R17)

PHP provides a robust set of array-manipulation functions that treat arrays as versatile data structures, supporting both indexed and associative storage. Key aspects include:

• Array Creation and Initialization: Arrays are created using the array() construct or the short [] syntax, supporting mixed data types.
• Sorting Functions: PHP offers specialized sorting such as sort(), rsort() for indexed arrays, and asort(), ksort() for associative arrays to maintain key-value relationships.
• Stack and Queue Operations: Arrays can function as stacks or queues using functions like array_push(), array_pop(), array_shift(), and array_unshift().
• Searching and Filtering: Functions like in_array() allow for existence checks, while array_filter() and array_map() provide functional programming capabilities to process or transform array elements based on callback logic.
• Merging and Slicing: Arrays can be combined using array_merge() or partitioned using array_slice() and array_splice() for dynamic data management.

Reading data from a web form in PHP involves accessing superglobal arrays that capture input based on the HTTP method specified in the form tag.

• Form Definition: The HTML form must specify the method attribute as either GET or POST.
• Accessing GET Data: When method='GET' is used, form data is appended to the URL and accessed via the $_GET associative array.
• Accessing POST Data: When method='POST' is used, data is sent in the request body, which is more secure for sensitive information, and accessed via the $_POST superglobal.
• Implementation Example: To retrieve a field named 'username', use the syntax
  $user = $_POST['username'];
• Validation: It is essential to use functions like isset() or empty() to verify that the form data exists before processing it to prevent undefined index errors.