Question: What are type casting and juggling? 

Ans:  Type casting:  converting values from one data type to another is known as type casting.
         Juggling: Automatic conversion is known as type juggling.

Question:What is the difference between sizeof($array) and count($array)? 

sizeof($array) - This function is an alias of count()
count($array) - If you just pass a simple variable instead of an array it will return 1.

Question:What are the different types of errors in PHP? 

1. Notices: These are trivial, non-critical errors that PHP encounters while executing a script - for example,
accessing a variable that has not yet been defined. By default, such errors are not displayed to the user at all
- although you can change this default behavior.2. Warnings: These are more serious errors - for example, attempting to include() a file which does not exist.
By default, these errors are displayed to the user, but they do not result in script termination.3. Fatal errors: These are critical errors - for example, instantiating an object of a non-existent class, or calling
a non-existent function. These errors cause the immediate termination of the script, and PHP’s default
behavior is to display them to the user when they take place.

Question:Between echo () and print () functions which one is the faster and why?

 

The echo () function is a tad faster because it returns nothing, whereas print() will return 1 if the statement is successfully output.

Question:What are type casting and juggling? 

Casting: Converting values from one data type to another is known as type casting. This is accomplished by placing the intended type in front of the variable to be cast.example:
$x=34.54;
$y=(int)$x;
echo $y; // returns 34Juggling: Variables are sometimes automatically cast to best fit the circumstances in which they are referenced. This is known as Type Juggling.example:
$a="34 items"
$total=5;
$total+=$a;
echo $total;// returns 39

Question:What type of inheritance that PHP supports?
            

The object-oriented development methodology places great stock in the concept of inheritance.This strategy promotes code reusability. PHP generally supports single type of inheritance.

Question:What is constant? How can you declare a constant? 

A constant is a value that cannot be modified throughout the execution of a program. Constants are particularly useful when working with values that definitely will not require modification, such as Pi (3.141592). Once a constant has been defined, it cannot be changed (or redefined) at any other point of the program. Constants are defined using the define() function in php.

Question:What is x+ mode in fopen() used for? 

Read/Write. Creates a new file. Returns FALSE and an error if file already exists

Question:What is constant? How can you declare a constant? 

A constant is a value that cannot be modified throughout the execution of a program. Constant are declare by using the define() function.Its prototype follows:

boolean define(string name, mixed value)Example
define("PI",3.14159);
echo PI; //returns 3.14159

Question:Which functions are used to add file in a script?

 

PHP offers four function for including files into applications. These are:

include(), require(), include_once(), require_once().