QB64-PE/internal/help/SELECT_CASE.txt

'''SELECT CASE''' is used to determine the program flow by comparing the value of a variable to specific values.


{{PageSyntax}}
:::::SELECT CASE variable
::::::' [[CASE]]
::::::' [[CASE IS]]
::::::' [[CASE ELSE]]
:::::[[END SELECT]] 


* Variable can be any literal string or numerical type. Can only evaluate ONE value or calculation.
* Use SELECT CASE when IF statements get too long or complicated.
* The CASE comparisons should cover the normal ranges of the variable values(use CASE ELSE if necessary).
* CASEs should be listed in an ascending or descending values for best and fastest results.
* The routine will execute code in the FIRST True [[CASE]] statement and exit the procedure.
* Supports individual CASE values and ranges or lists of values as below:
:* CASE value
:* CASE value1 [[TO]] value2
:* CASE value1, value2, value3
:* [[CASE IS]] value1 > value2
:* [[CASE ELSE]]

* SELECT CASE statements must '''always''' be ended with [[END SELECT]]!
* Use '''[[colon]]s''' to execute multiple statements in a one line statement. You cannot use AND for multiple statements!
* An '''[[underscore]]''' can be used anywhere after the code on one line to continue it to the next line in '''QB64 ONLY'''.


''Example:''
{{CodeStart}}
a = 100
{{Cl|SELECT CASE}} a          'designate the value to compare
  {{Cl|CASE}} 1, 3, 5, 7, 9
    {{Cl|PRINT}} "This will not be shown."
  {{Cl|CASE}} 10
    {{Cl|PRINT}} "This will not be shown."
  {{Cl|CASE}} 50
    {{Cl|PRINT}} "This will not be shown."
  {{Cl|CASE}} 100
    {{Cl|PRINT}} "This will be displayed when a equals 100)"
    {{Cl|PRINT}} "(and no other case will be checked)"
  {{Cl|CASE}} 150
    {{Cl|PRINT}} "This will not be shown."
  {{Cl|CASE IS}} < 150
    {{Cl|PRINT}} "This will not be shown as a previous case was true"
  {{Cl|CASE}} 50 {{Cl|TO}} 150
    {{Cl|PRINT}} "This will not be shown as a previous case was true"
  {{Cl|CASE ELSE}}
   {{Cl|PRINT}} "This will only print if it gets this far!"
{{Cl|END SELECT}} '' ''
{{CodeEnd}}
{{OutputStart}} 
This will be displayed when a equals 100)
(and no other case will be checked)
{{OutputEnd}}
:''Explanation:'' The first case where a value is true is shown, the remainder are skipped. Try changing the value of 'a' to different numbers!



''See also:'' 
* [[CASE]], [[CASE IS]]
* [[IF...THEN]], [[Boolean]]


{{PageNavigation}}