Campbell-scientific CR9000X Measurement and Control System Uživatelský manuál stáhnout pdf (Strana 347)

Section 9. Program Control Instructions

Select Case Statement

Executes one of several statement blocks depending on the value of an

expression.

Syntax

Select Case testexpression

[

Case expressionlist1

[statementblock-1] ]

[

Case expressionlist2

[statementblock-2] ]

[

CaseIs expressionlist2

[statementblock-n] ]

[

Case Else

[statementblock-n] ]

End Select

The Select Case syntax has these parts:

Part Description

Select Case Begins the Select Case decision control structure. Must appear before

any other part of the Select Case structure.

testexpression Any numeric or string expression. If testexpression matches the

expressionlist associated with a Case clause, the statementblock

following that Case clause is executed up to the next Case clause, or

for the final one, up to the End Select. Control then passes to the

statement following End Select. If testexpression matches more than

one Case clause, only the statements following the first match are

executed.

Case Sets apart a group of CRBasic statements to be executed if an

expression in expressionlist matches testexpression.

expressionlist The expressionlist consists of a comma-delimited list of one or more of

the following forms.

expression

expression To expression

Is compare-operator expression

statementblock

Elements statementblock-1 to statementblock-n consist of any number

of CRBasic statements on one or more lines.

Case Is Keyword used before a comparison operator (=, <>, <, <=, >, or >=). If

the Is keyword is not used (ie: Case < 10), the program will not

compile. If Case Is Expression List is used (ie: Case Is 15), the

comparitor is assumed to be the equal sign (equivalent to Case Is = 15).

Case Else Keyword indicating the statementblock to be executed if no match is

found between the testexpression and an expressionlist in any of the

other Case selections. When there is no Case Else statement and no

expression listed in the Case clauses matches testexpression, program

execution continues at the statement following End Select.

End Select Ends the Select Case. Must appear after all other statements in the

Select Case control structure.

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