Conditional statements and conditional sentences

• A conditional statement is used to determine the truth value of a condition and to specify the subsequent action in the object program on the basis of this value.

  Conditional statements include:

  • IF, EVALUATE, SEARCH and RETURN statements;

  • OPEN DOCUMENT statements which contain the (NOT) AT-END phrase;

  • READ statements which contain the (NOT) AT END or (NOT) INVALID KEY phrase;

  • WRITE statements which contain the (NOT) INVALID KEY or (NOT) END-OF-PAGE phrase;

  • START, REWRITE or DELETE statements which contain the (NOT) INVALID KEY phrase;

  • ADD, COMPUTE, DIVIDE, MULTIPLY or SUBTRACT statements which contain the (NOT) ON SIZE ERROR phrase;

  • STRING and UNSTRING statements which contain the (NOT) ON OVERFLOW phrase;

  • CALL statements which contain the ON OVERFLOW or (NOT) ON EXCEPTION phrase;

  • ACCEPT or DISPLAY statements which contain the (NOT) ON EXCEPTION phrase;

  • an INVOKE statement containing the (NOT) ON EXCEPTION phrase.

• A conditional sentence is a conditional statement which may optionally be preceded by an imperative statement and which is terminated by a period followed immediately by a space.