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50 lines
1.4 KiB
Plaintext
50 lines
1.4 KiB
Plaintext
[[ON...GOTO]] is a control-flow statement that branches to a line or label in a list depending on a numerical expression.
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{{PageSyntax}}
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: '''ON''' {{Parameter|numericalExpression}} [[GOTO]] {{Parameter|labelOrNumber}}[,{{Parameter|labelOrNumber}}][,...]
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{{PageDescription}}
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* {{Parameter|numericalExpression}} represents the ''line'' or ''label'' that the program should branch to: 1 branches to the first line or label in the list, 2 branches to the second, etc.
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* The procedure must be used after the number value is determined or in a loop to monitor current user events.
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* '''Note:''' [[SELECT CASE]] provides a much more convenient way of doing this task.
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{{PageQBasic}}
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* In QuickBASIC 4.5 the list could contain a maximum of 60 line numbers or labels, while '''QB64''' has no limit.
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{{PageExamples}}
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''Example:'' Changing the program flow when a value is not 0.
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{{CodeStart}} '' ''
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{{Cl|CLS}}
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a = 2
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{{Cl|ON...GOTO|ON a GOTO}} hello, hereweare, 143
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{{Cl|END}}
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hello:
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{{Cl|PRINT}} "you don't get to see this!"
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{{Cl|END}}
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hereweare:
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PRINT "And here we are..."
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END
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143
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PRINT "you don't get to see this neither..."
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END '' ''
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{{CodeEnd}}
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{{OutputStart}}
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And here we are...
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{{OutputEnd}}
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''Explanation:'' Since ''a'' equals 2 it goes to the second item in the list (hereweare) and branches to there. Try changing ''a' to 1 or 3.
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{{PageSeeAlso}}
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* [[ON...GOSUB]]
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* [[GOTO]]
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* [[GOSUB]]
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* [[SELECT CASE]]
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{{PageNavigation}}
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