PHP

PHP

Ch-1

Q1. Who is the developer of php and when it was first developed?

Ans: Rasmus Lerdorf is the developer of php and it was first developed in 1995.

Q2. What are the general language features of php?

Ans: Practicality: It allows the user to build powerful applications even with a minimum of knowledge.

        Power: It has the ability to interface with databases, manipulate from information, and create pages dynamically.

      Possibility: It rarely bound to any single implementation solution.

       Price: It is free of charge.

Ch-2

Q3.What are the four configuration Directive scopes?

Ans:

1.      PHP_INI_PERDIR

2.       PHP_INI_USER

3.       PHP_INI_SYSTEM

4.      PHP_INI_ALL.

Q4. What are the configurations files of php and apache?

Ans:

PHP: The php.ini file is a simple text file, consisting solely of comments and the directives and their corresponding values.

Apache:  apache.httpd.conf and .htaccess - When PHP is running as an Apache module, you can modify many of the directives through either the httpd.conf file or the .htaccess file.

Ch-3

Q5. Between echo () and print () functions which one is the faster and why?

Ans.

1.      echo() is faster because it returns nothing(value) whereas print() returns value.

2.      echo can take multiple parameters while print can take one argument.

Q6. Which function is used to print the output in a variable?

Ans. Sprint() function assigns the output to a string variable rather than renders to the browser.

Q7. 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.

Q8. Which variable keeps its value after functions exits?

Ans: Static variable keeps its value after functions exits because it does not lose its value when the function exits.

Q9. What is constant? How can you declare a constant?

Ans: A constant is a value that can’t be modified throughout the execution of a program. Constant are declared by using the define () function.
Ex- define("PI", 3.141592);

Q10.How foreach loop works?

Ans: For each loop is used to get value from a list/array. It is undefined how many times the loop will be iterated. This loop stripes each value from the array and moving the pointer closer to the end by each iteration.

Q11. Which functions are used to add file in a script?

Ans: include(): The include() statement will evaluate and include a file into the location where it is called.
require (): require() operates like include(), including a template into the file in which the require() call is located.

Ch-4

Q12. What are passing arguments by reference and passing arguments by value?

If we want any changes made to an argument within a function to be reflected outside of the function’s scope, passing the argument by reference accomplishes this. Passing an argument by reference is done by appending an ampersand to the front of the argument.

If we declare a variable and use it as an argument of a function, it’s called passing arguments by value. Any changes made to the value of that variable within the scope of the function are ignored outside of the function.

Q13. What is recursive function?

Recursive functions are functions that call themselves. They offer considerable practical value to the programmer and are used to divide a complex problem into a simple case, reiterating that case until the problem is resolved.

Ch-5

Q14. What are the types of key of array?

1.    Numerical keys bear no real relation to the value other than the value’s position in the array

2.    Associative key logically bears a direct relation to its corresponding value.

Q15. Which functions are used to add and remove array elements?

array_unshift: Adds elements to the front of the array.

array_push: Adds elements to the end of the array.

array_shift: Removes the first element in an array.

array_pop: Removes the last element in an array.

Ch-6

Q17. What are the three object-oriented features?

Encapsulation: The practice of separating the user from the true inner workings of an application through well-known interfaces is known as encapsulation.

Inheritance:

Polymorphism: defines OOP’s ability to redefine a class’s characteristic or behavior depending upon the context in which it is used.

Q19. What are class and object?

Class: A class is used in OOP to describe one or more objects. It serves as a template for creating, or instantiating, specific objects within a program.

Object:  "object" refers to a particular instance of a class where the object can be a combination of variables, functions, and data structures.

Q20. What are the five property scopes?

   PHP supports five class property scopes: public, private, protected, final, and static.

Q21. What is property overloading?

Ans: Property overloading continues to protect properties by forcing access and manipulation through public methods, yet allowing the data to be accessed as if it were a public property

Q22. What are constructor and destructor?

Constructor: a constructor is defined as a block of code that automatically executes at the time of object instantiation.

Destructor: is like a constructor. It automatically destroys the objects when they are no longer needed.

Ch-7

Q23. What is object cloning?

Ans: Object cloning is the act of making a copy of an object.

$drone1 = new Corporate_Drone();

$drone2 = clone $drone1;

Q24. What type of inheritance that PHP supports?

Ans: Class Inheritance, Inheritance and Constructors, Inheritance and Late Static Binding.

Q25. What are the abstract class and interface?

An interface allows us to create code which specifies which methods a class must implement, without having to define how these methods are handled.

An abstract class is a class that really isn’t supposed to ever be instantiated but instead serves as a base class to be inherited by other classes.