Sorting is a process to arrange the records in the file in an order(either ascending or descending) with respect to the key.

Sorting can be divided into two types of categories called internal and external sorting based on location of records at the time of sorting.

The characteristics of sorting methods are – Data Sensitivity, Stability, Storage Requirements, Efficiency

Characteristics of Sorting methods
—————————————————-

• Data Sensitiveness
• Stability
• Storage Requirements
• Efficiency

Data Sensitiveness: The sorting methods for which the time to sort an array depends on the order in which the elements appear in the original array (i.e., Sorted or Unsorted). are called Data Sensitive Methods.

Stability: Methods that preserve the original ordering of elements are called stable methods.

Storage requirements: Minimal storage sorting methods are those methods that use minimal storage space by rearranging the elements with the space occupied by the original array.

Efficiency: Efficiency is the tome required to the array by any sorting method depending upon the number of comparisons required for that sorting method.

Types of Sorting
————————-
1. Bubble sort
2. Selection sort
3. Quick sort
4. Insertion sort
5. Merge sort
6. Heap sort
Bubble sort: This method works according to exchange sort technique,where the records are physically interchanged within the file according to their key values
Bubble sort is data sensitive. The number of checking required may be anything between 1 to (n-1) where ‘n’ denotes the number of elements in the array.

Quick sort: Fast method of internal sorting. Uses divide and conquer method of sorting

Insertion sort: Compares the elements of the array in the growing order successively.

Two variations of this insertion

Shuttle sort – Requires (n-1)rounds of checking if there are n elements in the array

Shell sort– Similar to the shuttle sort but sorts the arrays in the ascending order.

Merge Sort: Merging means combining two sorted arrays into single sorted array.

Steps in the process:
Scan both the arrays for right to left
Compare the first element of each array
The above step is repeated until one array is completely empty.
The remaining elements in the other array are stored in the merged array in the order as they were in.

Heap Sort: The value at each node in a heap (Binary tree)
is larger than the value at its existing children. The root contains the largest item.

You can also refer data structure graph here

The post Sorting technique appeared first on .

Subscript Array is a structure storing elements of similar data types sequentially in memory (Index) is a variable through which the elements of the array are processed.

Array size is maximum number of elements an array can hold.

Rules for Arrays:-

• An array must be declared before it is used.
• An array name has the same rules applicable to it that are defined for variable names.
• An array name cannot be the same as an existing variable name or constant name.
• Array size specified in the declaration statement must be a positive integer value or a constant containing a positive integer value.
• It is invalid to assign an array to another by using the assignment operator. For example, If num and num2 are  arrays, it is invalid to write num2 = num.

The post Arrays and Functions appeared first on .

<?php
$arr = array('Apple', 'Zensor', 'MITIndia');
echo "<br><b>Without sorted values are..</b><br>";

echo $arr[0], "<br>";
echo $arr[1], "<br>";
echo $arr[2], "<br>";

echo "<br><b>Sorted values are..</b><br>";
sort($arr);
$len=count($arr);
for($i=0; $i<$len; $i++)
{
echo $arr[$i], "<br>";
}

echo "<br><b>Reverse sorted values are..</b><br>";
rsort($arr);
$len=count($arr);
for($i=0; $i<$len; $i++)
{
echo $arr[$i], "<br>";
}
?>

Out put of the above program is… (function sort() to use display records in ascending and function rsort() to display in descending order.)

PHP Program to compress the data / text.

<?php
echo "<h1> Compress character with PHP </h1>";
echo "<hr>";
$str="Hello World Hello WorldHello WorldHello WorldHello 

WorldHello WorldHello WorldHello WorldHello WorldHello 

WorldHello WorldHello WorldHello WorldHello WorldHello 

WorldHello WorldHello WorldHello WorldHello WorldHello 

WorldHello WorldHello WorldHello World";
 
$compressed = gzcompress($str);
echo "Original file length: ". strlen($str)."\n";
echo "Compressed size: ". strlen($compressed)."\n";
?>

Output of the above program is…

PHP Program to display server date and time.

<?php
echo "Today date :", date("m/d/y");
echo "<br>The time is " . date("h:i:sA");
echo "<br>";
echo date('d-m-Y H:i');
echo "<br>";
?>

[m=month, d=day, y=year, h=hours, i=minutes, s=seconds  and A=ante meridiem]   Output of the above program is…

The post PHP Array and Compressing Data appeared first on .