| **Navigation:**  [[introduction.htm|Language Reference]] > 2 - Program Source Code Format > Statement Format >====== Structure Termination ====== | [[declaration and statement labels.htm|{{btn_prev_n.gif|Previous page}}]][[introduction.htm|{{btn_home_n.gif|Return to chapter overview}}]][[field qualification.htm|{{btn_next_n.gif|Next page}}]] | | || Compound data structures are created when data declarations are nested within other data declarations. There are many compound data structures within the Clarion language: APPLICATION, WINDOW, REPORT, FILE, RECORD, GROUP, VIEW, QUEUE, etc. These compound data structures must be terminated by a period (.) or the keyword END. IF, CASE, EXECUTE, LOOP, BEGIN, and ACCEPT are all executable control structures. They must also be terminated with a period or the END statement (a LOOP may optionally terminate with a WHILE or UNTIL statement).