The statement following DO is executed. The Boolean expression is evaluated, and if it is FALSE, the statement is executed again and the Boolean expression is reevaluated. This sequence of operations continues until the value of the Boolean expression is TRUE. At that time, control passes to the statement following the DO statement.

Note that both <block> and <compound statement> are statements and can be substituted for <statement>.

DO-UNTIL Loop illustrates the DO-UNTIL loop.