PHP/Statement/switch statement
Содержание
- 1 A switch Statement
- 2 A switch Statement for string
- 3 In a switch/case block, you specify what you are checking against, then give a list of possible values you want to handle.
- 4 Omitting the break statement can be useful in some cases
- 5 Switch and constants
- 6 switch command for string value
- 7 Switch Statement
- 8 Use the "default" case
- 9 Using endswitch to end the switch definition
- 10 Using switch to test for multiple values
- 11 Using the DEFAULT: statement to generate an error
- 12 Using the switch Statement
- 13 What happens when there are no break keywords
A switch Statement
<source lang="html4strict">
<html> <head><title>A switch Statement</title></head> <body>
<?php
$satisfied = "no"; switch ( $satisfied ) { case "very": print "very"; break; case "no": print "no"; break; default: print "default"; }
?>
</body> </html>
</source>
A switch Statement for string
<source lang="html4strict">
<html> <head> <title>A switch Statement</title> </head> <body> <?php $mood = "sad"; switch ( $mood ) {
case "happy": print "I"m in a good mood"; break; case "sad": print "Don"t be down!"; break; default: print "Neither happy nor sad but $mood";
} ?> </body> </html>
</source>
In a switch/case block, you specify what you are checking against, then give a list of possible values you want to handle.
<source lang="html4strict">
<?php
$Name = "Bob"; switch($Name) { case "Jim": print "Your name is Jim\n"; break; case "Sally": print "Your name is Sally\n"; break; default: print "I don"t know your name!\n"; } ?> </source>
Omitting the break statement can be useful in some cases
<source lang="html4strict">
<?
$aColor = "Red"; switch( $aColor ) { case "red": case "Red": // The following prints if $aColor is // either "red" or "Red" print( "#FF0000
" ); break; case "green": case "Green": print( "#00FF00
" ); break; case "blue": case "Blue": print( "#0000FF
" ); break; default: print( "other
" ); break; }
?>
</source>
Switch and constants
<source lang="html4strict">
<?php define("ALIGN_LEFT", 1); define("ALIGN_CENTER", 2); define("ALIGN_RIGHT", 3); switch($value) {
case ALIGN_LEFT : break; case ALIGN_CENTER : break; case ALIGN_RIGHT : break;
} ?>
</source>
switch command for string value
<source lang="html4strict"> <?php $choice = "Rock"; switch ($choice){ case "Pop": print "Pop not Rock"; break; case "Rap": print "Rap and not Rock"; break; case "Jazz": print "Jazz not Rock"; break; case "Rock": print "Rock music"; break; } ?> </source>
Switch Statement
<source lang="html4strict">
<html>
<head> <title>Switch Statement</title> </head> <body> <?php $num = 2; switch($num) { case 1 : echo("This is case 1 code"); break; case 2 : echo("This is case 2 code"); break; case 3 : echo("This is case 3 code"); break; default : echo("This is default code"); } ?> </body>
</html>
</source>
Use the "default" case
<source lang="html4strict">
<?
$nIndex = 17; switch ( $nIndex ) { case 0: print( "zero
" ); break; case 1: print( "one
" ); break; case 2: print( "two
" ); break; default: print( "neither zero, one nor two
" ); break; }
?>
</source>
Using endswitch to end the switch definition
<source lang="html4strict">
<? $action= "ADD"; switch ($action):
case "ADD": echo "Perform actions for adding."; break; case "MODIFY": echo "Perform actions for modifying."; break; case "DELETE": echo "Perform actions for deleting."; break; default: echo "Error: Action must be either ADD, MODIFY, or DELETE.";
endswitch; ?>
</source>
Using switch to test for multiple values
<source lang="html4strict">
<? $action = "ADD"; switch ($action) {
case "ADD": echo "Perform actions for adding."; break; case "MODIFY": echo "Perform actions for modifying."; break; case "DELETE": echo "Perform actions for deleting."; break;
} ?>
</source>
Using the DEFAULT: statement to generate an error
<source lang="html4strict">
<? $action= "ADD"; switch ($action) {
case "ADD": echo "Perform actions for adding."; break; case "MODIFY": echo "Perform actions for modifying."; break; case "DELETE": echo "Perform actions for deleting."; break; default: echo "Error: Action must be either ADD, MODIFY, or DELETE.";
} ?>
</source>
Using the switch Statement
<source lang="html4strict">
<?php
$i = 0; switch($i) { case 1: echo "First case
"; case 2: echo "Second case
"; break; default: echo "Default case"; }
?>
</source>
What happens when there are no break keywords
<source lang="html4strict">
<? $action = "ORDER"; switch ($action) {
case "ORDER": echo "order assembly.
"; case "PACKAGE": echo "packing.
"; case "SHIP": echo "shipping.
"; }
?>
</source>