Friday, 20 October 2017

Constructor PHP

Constructor used in object oriented language for allocate space while creating object. A constructor also helps initialize a variable while declaring.

Every object oriented language built in support for programming. PHP is also a server side script and object oriented language. So should know how can you use constructor is elaborate in following example.

class Foo
$this->roll $roll;

Thursday, 19 October 2017

Compile time vs Run time error

Compile time
1.      The program need not satisfy any invariants. In fact, it needn't be a well-formed program at all. You could feed this HTML to the compiler and watch it barf...
2.      What can go wrong at compile time:
·         Syntax errors
·         Type checking errors
·         (Rarely) compiler crashes
3.      If the compiler succeeds, what do we know?
·         The program was well formed---a meaningful program in whatever language.
·         It's possible to start running the program. (The program might fail immediately, but at least we can try.)
4.      What are the inputs and outputs?
·         Input was the program being compiled, plus any header files, interfaces, libraries, or other voodoo that it needed to import in order to get compiled.
·         Output is hopefully assembly code or relocatable object code or even an executable program. Or if something goes wrong, output is a bunch of error messages.
Run time
1.      We know nothing about the program's invariants---they are whatever the programmer put in. Run-time invariants are rarely enforced by the compiler alone; it needs help from the programmer.
2.      What can go wrong are run-time errors:
·         Division by zero
·         Dereferencing a null pointer
·         Running out of memory
Also there can be errors that are detected by the program itself:
·         Trying to open a file that isn't there
·         Trying find a web page and discovering that an alleged URL is not well formed
3.      If run-time succeeds, the program finishes (or keeps going) without crashing.
4.      Inputs and outputs are entirely up to the programmer. Files, windows on the screen, network packets, jobs sent to the printer, you name it. If the program launches missiles, that's an output, and it happens only at run time :-)

 Example compile time error

Wednesday, 18 October 2017

Array vs Link List

Sr No.
Link List
An array is a collection of similar data type
A link list a collection of similar objects which may have array
Space allocation continuous
Space allocation random
Element of an array is access through its index
Data of link list access through self-referential pointer

Monday, 16 October 2017

Matrix Diagonal Sum

Q : Write a ‘C’ program to find out sum of diagonal elements of a matrix using ‘C’.

Solution : 

#define MAX 3
void main()
     int ar[MAX][MAX],i,j,r,c,sum=0;
              printf("Enter Number>> ");

Saturday, 14 October 2017



<!DOCTYPE html>
    <script type="text/javascript" src=""></script>
    <input id="searchInput" class="input-controls" type="text" placeholder="Enter a location">
    <div class="map" id="map" style="width: 100%; height: 300px;"></div>
    <div class="form_area">
        <input type="text" name="location" id="location">
        <input type="text" name="lat" id="lat">
        <input type="text" name="lng" id="lng">
        /* script */

Monday, 9 October 2017

UGC Net Computer Science Paper 3 Dec 13 Page 7

61. Which of the following is not true with respect to a trackball and/or spaceball ?
I. A trackball is a two dimensional positioning device while as a spaceball provides six degrees of freedom.
II. Unlike the trackball a spaceball does not actually move.
III. A trackball is a three dimensional positioning device while as a spaceball provides six degrees of freedom.

(A) I & II
(B) II & III
(C) II only
(D) III only

62. Which of the following statement(s) is (are) true ?
I. Two successive translations are additive.
II. Two successive rotations are additive.

UGC Net Computer Science Paper 3 Dec 13 Solved Page 6

UGC Net Computer Science Paper 3 Dec 13 Solved Page 6
51. Synchronization is achieved by a timing device called a ________ which generates a periodic train of ________.
(A) clock generator, clock pulse
(B) master generator, clock pulse
(C) generator, clock
(D) master clock generator, clock pulse

UGC Net Computer Science December 13 Paper 3 Page 5 Solved

40.  Pumping lemma for context-free languages states : Let L be an infinite context free language. Then there exists some positive integer m such that any w ∈ L with |w| ≥ m can be decomposed as
w = uv xy Z with |vxy| _________ and |vy| _________ such that 
Z ∈ L for all .z = 0, 1, 2, ....... .
(A) ≤ m, ≤ 1
 (B) ≤ m, ≥ 1
(C) ≥ m, ≤ 1
(D) ≥ m, ≥ 1

Saturday, 7 October 2017

C Language Model Question Set2

C Language

Name : ______________________                                                                                                        Time :________________
Part 1

Q 1. Which one of the following translate or convert high level language program line by line.
A) Translator  
D) None

Friday, 6 October 2017

Javascript Random Number

Math.random function is use to generate random number. It generates a long series of number less than one or zero. To get random number from a range you need to extract numbers as your requirement by round-off.

Following code demonstrate to generate number from 1 to 100.

     <title>Girfa Student Help : Random Number</title>
          function getRandom()

Thursday, 5 October 2017

Timer Java Script

Timer Java Script Banner

A timer like simulation can be creating using setTimeOut function which takes two arguments. code and timer interval in Millisecond. Code run after given time span and if you will call these function in recursive fashion then you can make a watch. 

Timer function Function 

          var s=0,m=0,h=0;
          function getTimer()
              if(s==5) //Minute complete

Tuesday, 3 October 2017

UGC Net Computer Science December 13 Paper 3 Page 4 Solved

UGC Net Computer Science December 13 Paper 3 Page 4 Solved

31. Consider the formula in image

CR is called as compression ratio n1 and n2 denotes the number of information carrying units in two
datasets that represent the same information. In this situation RD is called as relative _________ of the
first data set.
(A) Data Compression
(B) Data Redundancy
(C) Data Relation
(D) Data Representation

Monday, 2 October 2017

Linear Search VS Binary Search

A linear search works by looking at each element in a list of data until it either finds the target or reaches the end. This results in O(n) performance on a given list. A binary search comes with the prerequisite that the data must be sorted. We can leverage this information to decrease the number of items we need to look at to find our target. We know that if we look at a random item in the data (let's say the middle item) and that item is greater than our target, then all items to the right of that item will also be greater than our target. This means that we only need to look at the left part of the data. Basically, each time we search for the target and miss, we can eliminate half of the remaining items. This gives us a nice O(log n) time complexity.

Just remember that sorting data, even with the most efficient algorithm, will always be slower than a linear search (the fastest sorting algorithms are O(n * log n)). So you should never sort data just to perform a single binary search later on. But if you will be performing many searches (say at least O(log n) searches), it may be worthwhile to sort the data so that you can perform binary searches. You might also consider other data structures such as a hash table in such situations.

Image Source :

Example : Array is best example of linear search and tree

CSS 360 Rotation

CSS 360 Rotation

Girfa : Student help

Hover the Mouse on div


div {
    width: 100px;
    height: 100px;
    background: red;
    -webkit-transition-property: all; /* Safari */
    -webkit-transition-duration: 2s; /* Safari */
    transition-property: all;
    transition-duration: 1s;