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Description |
The while statement gives a one or more instructions to be repeated a specified number of times. | ||||||||||||||||||||||||||||
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Syntax |
While condition do action | ||||||||||||||||||||||||||||
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Parameters |
condition The condition controls the statement. Each passage through the statement, the condition is evaluated. When the condition is satisfied, the statement ends.
do do is a convention of the while() statement. It introduces the action.
action The action is the instruction to be repeated. To write multiple instructions, use a begin/end block. | ||||||||||||||||||||||||||||
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Return Value |
NA | ||||||||||||||||||||||||||||
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Examples |
fact4(n)=begin result=1 while n>0 do begin result=result*n n=n-1 end result end | ||||||||||||||||||||||||||||
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Comments |
In the example, the calling formula passes a value to the argument n. fact4() then declares a variable result equal to 1. The while statement uses the begin/end keywords so that both of the lines within the begin/end block repeat “while” the value of n is greater than zero. The first line within the while statement sets the value of result equal to the product of the current value of result multiplied by the argument n. The second line within the while statement decrements the value of n by 1. Finally, the formula returns the value of result.
The following table summarizes how the return value of a call to fact4() with an argument of 5 is determined:
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