Programming In QuickBASIC

3.5 Selection

Selection is a fundamental building block of a structured language.

3.5.1 IF - END IF Structures

The IF - END IF structure is a decision structure that allows different courses of action to occur.

IF <condition> THEN
   - - -
ELSEIF
   - - -
ELSE
   - - -
END IF

3.5.2 SELECT CASE Structures

The SELECT CASE structure is an alternative to IF - END IF. It is preferable to use when there is a large number of alternative actions.

SELECT CASE <variable>
   CASE IS <condition>
   CASE <value>
   CASE <min> TO <max>
   CASE ELSE
END SELECT

• All CASE statements refer to the variable on the top line.
• CASE arguments can be a list of values separated by commas.
• Ranges can be used where to values are separated by TO.
• CASE statements can be followed by an relational operator.
• CASE ELSE is an optional "catch all" if any other CASE statements are not executed.
• Only 1 CASE statement can be executed.

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