Looping while a condition is satisfied

   

Syntax

BD>while : E

BD>...

BD>...Body of commands

BD>...

BD>wend :

where E is any valid equation.

The WHILE:  ...WEND:  construction is used to provide a loop surrounding a body of commands which will be processed as long as the rounded value of the equation E remains TRUE. An equation is defined to be TRUE if the rounded value of the equation is equal to unity, and FALSE otherwise. If no equation is given, or if a mistake is made in determining the equation, then [B/D] assumes that a valid equation with value FALSE has been supplied, so that the commands in the loop will not be processed.

Both the initiating WHILE:  and the terminating WEND:  command must be given on a separate line, and you should be careful not to confuse separate while ...end structures where you are nesting them.

As an example, consider the following program fragment.

BD>c : %i=0

BD>while : %i<2

BD>c : %i=%i+1

BD>c : %j=0

BD>repeat :

BD>c : %j=%j+1

BD>print : (%i), (%j)

BD>until : %j=2

BD>wend : %i=2

This code establishes two loops during which the constants take the values (%i=1,%j=1), (%i=1,%j=2), (%i=2,%j=1), (%i=2,%j=2), and then terminate.

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