Interview Questions Unit 1 !!
|1. Explain the concept of Object Oriented Programming Paradigm ?
OOPs stands for Object Oriented Programming Language. Object oriented concept enabled the concept of writing programs formulated as object type. The introduction to object type methodology introduced various validations as well security issues for web as well as mobile based application. Object-oriented programming (OOP) is nothing but that which allows the writing of programs with the help of certain classes and real-time objects. We can say that this approach is very close to the real-world and its applications because the state and behaviour of these classes and objects are almost the same as real-world objects.
The main features of oops are as follows :
1.Encapsulation : Encapsulation came up from the word capsule and resembles the same working funda. Encapsulation refers to the concept of capsuling or assembling various data types and methods under one name which can be used as a single unit for a specific task.
2. Abstraction and Data Hiding : Abstraction refers to hiding the internal details and showing only the essential features. Elaborating it , I would like to point out – its not necessary for one to know all the internal working features of any application or web site like wise I don’t want to know what language used to develop for a particular web site , I just need the set up to be aim oriented , fast and effective.
3.Inheritance : Inheritance refers to gaining the properties of previous or base class to the new or child class. This introduces the concept of re usability. The one set up which we have already defined in the previous class needs not to be implemented in the new class, we can all it and all the properties for the main or mother class gets to the new class.
4. Polymorphism refers to taking more than one forms. Poly means many and morphism means forms. Taking more than one forms. It elaborates the concept how any function or operator can take different form with the same name. It is further divided overloading and over riding.
Overloading : In this section it is further categorized as function overloading and operator overloading.
Function Overloading : Function refers to the concept as , when two functions have the same name but different parameters.
Operator overloading : Refers to the concept where an operator exhibits different properties at different situations.
Over riding : Over riding refers to the concept of erasing the previous properties and depicting the new property defined.
5.Dynamic binding : Dynamic binding is one of the most important concept and finds its application in almost all the technologies. It is referring to dynamically holding the memory or variable which is directly dependent on the user. It depends in the users input – what type of memory should be allocated to the variable.
6.Classes and Objects : Class is an abstract and user-defined data type. It consists of several variables and functions. The primary purpose of the class is to store data and information. The members of a class define the behavior of the class. A class is the blueprint of the object, but also, we can say the implementation of the class is the object. The class is not visible to the world, but the object is.
|2. Elaborate Procedure Oriented Language ?
Procedure Oriented Programing concept we divide programs in functions. Every functions or variable in the approach are public and global. There is no any validations or restrictions imposed. These programming constructs were developed in the late 1970s and 1980s. The basic drawback of the procedural programming approach is that data is not secured because data is global and can be accessed by any function. Program control flow is achieved through function calls and goto statements. The programming languages: FORTRAN (developed by IBM) and COBOL (developed by Dr Grace Murray Hopper) follow this approach.
|3. Elaborate the importance and working of Get Method
Using Get method you can forward the data from one page to another. Get method is used to transfer the data using the browser link where the data gets visible on the web browser. GET METHOD should only be used when any information, or not sensitive data is to be transferred from one page to another.
For Example : Page1
Welcome.PHP looks like:
Your email address is:
|4. What is the difference between echo and print statement in PHP ?
echo and print are more or less the same. They are both used to output data to the screen.
The differences are small: echo has no return value while print has a return value of 1 so it can be used in expressions. echo can take multiple parameters (although such usage is rare) while print can take one argument. echo is marginally faster than print.
|5. What is the relationship between cookies and sessions in web world ?
A cookie is a small file with the maximum size of 4KB that the web server stores on the client computer.
Once a cookie has been set, all page requests that follow return the cookie name and value.
A cookie can only be read from the domain that it has been issued from. For example, a cookie set using the domain www.noidatut.com can not be read from the domain http://noidatut.com/dprojects.php?spid=2
What is a Session?
A session is a global variable stored on the server.
Each session is assigned a unique id which is used to retrieve stored values.
Whenever a session is created, a cookie containing the unique session id is stored on the user’s computer and returned with every request to the server. If the client browser does not support cookies, the unique php session id is displayed in the URL
Sessions have the capacity to store relatively large data compared to cookies.
The session values are automatically deleted when the browser is closed. If you want to store the values permanently, then you should store them in the database.
Just like the $_COOKIE array variable, session variables are stored in the $_SESSION array variable. Just like cookies, the session must be started before any HTML tags.
You want to store important information such as the user id more securely on the server where malicious users cannot temper with them.
You want to pass values from one page to another.
You want the alternative to cookies on browsers that do not support cookies.
You want to store global variables in an efficient and more secure way compared to passing them in the URL
You are developing an application such as a shopping cart that has to temporary store information with a capacity larger than 4KB.