Looping until a condition is satisfied

   

Syntax

BD>repeat :

BD>...

BD>...Body of commands

BD>...

BD>until : E

where E is any valid equation.

The REPEAT:  ...UNTIL:  construction is used to provide a loop surrounding a body of commands which will be processed at least once, and will continue to be processed the equation E becomes TRUE. The 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 TRUE has been supplied, and the loop will not be repeated.

Both the initiating REPEAT:  and the terminating UNTIL:  command must be given on a separate line, and you should be careful not to confuse separate repeat ...until structures where you are nesting them.

As an example, consider the following program fragment.

BD>c : %i=0

BD>repeat :

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>until : %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.

• Other remarks