COBOL - Scope Terminators

A scope terminator ends a verb or statement. Scope terminators can be explicit or implicit.

Explicit scope terminators:

Explicit scope terminators end a verb without ending a sentence. They consist of END followed by a hyphen and the name of the verb being terminated, such as END-IF.

Listed below some of the important explicit scope terminators.

END-ADD
END-PERFORM
END-ACCEPT
END-CALL
END-COMPUTE
END-DELETE
END-DISPLAY
END-DIVIDE
END-EVALUATE
END-IF
END-MULTIPLY
END-READ
END-RETURN
END-REWRITE
END-SEARCH
END-START
END-STRING
END-SUBTRACT
END-UNSTRING
END-WRITE

Implicit scope terminator:

An implicit scope terminator is a period (.) that ends the scope of all previous statements not yet ended.

Example:

Let see example below with both implicit and explicit scope terminators.

Implicit scope terminator:

IF ITEM = "A"
    DISPLAY "THE VALUE OF ITEM IS " ITEM
    ADD 1 TO TOTAL
    MOVE "C" TO ITEM
    DISPLAY "THE VALUE OF ITEM IS NOW " ITEM.   ---> IF statement end here

IF ITEM = "B"
    ADD 2 TO TOTAL.    ---> IF statement end here

Explicit scope terminator:

IF ITEM = "A"
    DISPLAY "THE VALUE OF ITEM IS " ITEM
    ADD 1 TO TOTAL
    MOVE "C" TO ITEM
    DISPLAY "THE VALUE OF ITEM IS NOW " ITEM
END-IF    ---> IF statement end here

IF ITEM = "B"
    ADD 2 TO TOTAL
END-IF    ---> IF statement end here

For improved program clarity and to avoid unintentional ending of statements, use explicit scope terminators, especially within paragraphs. Use implicit scope terminators only at the end of a paragraph or the end of a program.

Tips:

Be careful when coding an explicit scope terminator for an imperative statement that is nested within a conditional statement. Ensure that the scope terminator is paired with the statement for which it was intended. In the following example, the scope terminator will be paired with the second READ statement, though the programmer intended it to be paired with the first.

READ FILE1
  AT END
    MOVE A TO B
    READ FILE2
END-READ

To ensure that the explicit scope terminator is paired with the intended statement, the preceding example can be recoded in this way.

READ FILE1
  AT END
    MOVE A TO B
    READ FILE2
    END-READ
END-READ

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