Decision Making Using PHP Switch Statement

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Submitted by haroon (Contact Author) (Forums) on Thu, 2007-01-25 11:00. :: PHP | PHP

Decision Making Using PHP Switch Statement 

Hi,

Here is a good shepherd with his sheep again.

Today I am going to discuss Switch Statement. The basic concept of Switch is similar to the IF-ELSE statement; it helps you to write decision making code just like IF-ELSE but it is a little more organized, elegant and handy when dealing with complex logics as compare to IF-ELSE.

Remember, you can convert every IF-ELSE programme to Switch syntax but vice versa is not possible in some situations.

Remember one more thing, it is not necessary to convert IF-ELSE to Switch and vice versa, just use whatever suits to your needs, though when handling the complex and large decision making code I would suggest to use Switch.

Let’s have a look at its syntax.

Switch Statement Syntax:

switch (input)
{
case condition1:
code to be executed if input = condition1;
break;
case condition2:
code to be executed if input = condition2;
break;
default:
code to be executed
if input is different
from both condition1 and condition2;
}

Explanation:

The parenthesis of Switch accepts a value which is matched with cases and if any case if found true the block of code for that case is executed. If the input doesn’t match with any of the cases then the code block under ‘default’ is executed.

every case is headed by keyword ‘case’ following by its value and a colon (:). Every case ends with a break statement.

What is break statement: break statement breaks the flow of a certain code block in which it resides and take the control out of the block. You can use break without switch statement too for example to take the control out from a FOR loop (will discuss later) or IF statement.

Let’s write a simple programme to understand the use of Switch statement in PHP.

<?php
 
$site = "Fast Creators";
 
switch ($site)  {
 
    case "Fast Creators":
     echo "<a href="http://fastcreators.com">www.fastcreators.com</a>";
    break;
 
    case "How To Forge":
     echo "<a href="http://howtoforge.com">www.howtoforge.com</a>";
    break;
 
    case "PHP Official Site":
     echo "<a href="http://php.net">www.php.net</a>";
    break;
 
default:
  echo "Input did not match with any case";
 
  }
?>

Here we have hard-coded $site value so the first case will stand true and the programme will display www.fastcreators.com and the break statement of case will take out the control from Switch body. ‘Default’ does not require any break statement as it is the last option of the switch statement.

Switch statement’s body starts and closes with braces.

Assignment:

Make a form that has different countries names in a drop-down list. After you select a country and submit the form the accepting page should use Switch statement to check the country name and then display its Capital, Currency Name and National Language.

You can post your assignments on haroon[at]fastcreators[dot]com.

Till we gather on another article take good care of yourself and keep practicing.

- Haroon Ahmad

Series: Fast PHP Articles

 


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