What control structures are there?
The IF statement first evaluates the search condition. If this is met, the statement specified in the THEN branch is executed. Otherwise, the statement in the ELSE branch (if defined) is executed. The WHILE statement enables statements to be repeated in response to certain conditions. The statement is executed as long as the search condition specified is met. The condition is checked, in particular, before the statement is executed for the first time. This means the statement may not be executed at all. By specifying BREAK, you can exit the loop straight away without the condition being checked. If CONTINUE is specified in the loop, the condition is revaluated immediately and the loop is processed again, or exited, depending on the result. The CASE statement allows the conditional execution of a statement, dependent on search conditions or the equality of operands. There are simple and general CASE statements.
