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DO…UNTIL

Repeats a set of instructions until a condition becomes true.

Syntax

DO UNTIL boolean_expression statements LOOP

or

DO statements LOOP UNTIL boolean_expression

Comments

boolean_expression is an expression that evaluates to true or false, such as I > 100.

The first form of the statement first test the boolean_expression. If the expression is true, QBasic skips the statements within the loop and continues execution at the first statement following the loop. If the expression is false, QBasic executes the statements within the loop until the boolean_expression is true.

The second form of the statement first performs the statements within the loop and then tests the boolean_expression. If the expression is false, QBasic repeats the statements in the loop. If the boolean_expression is true, QBasic continues execution at the first statement following the loop.

Example

i = 0
DO
  PRINT i
  i = i + 1
LOOP UNTIL i = 100

See Also