COBOL by Example: Sections
Organizing procedural code using sections within the PROCEDURE DIVISION as logical groupings of paragraphs, implementing the PERFORM statement to transfer control between sections and return after completion, structuring programs into modular units like initialization, processing, and cleanup, and preventing fall-through execution with proper control flow management using STOP RUN.
Code
IDENTIFICATION DIVISION.
PROGRAM-ID. SECTIONS-DEMO.
DATA DIVISION.
WORKING-STORAGE SECTION.
01 NUM1 PIC 99 VALUE 10.
PROCEDURE DIVISION.
MAIN-LOGIC SECTION.
DISPLAY "In Main Logic Section".
PERFORM CALCULATION-SECTION.
STOP RUN.
CALCULATION-SECTION.
ADD 5 TO NUM1.
DISPLAY "Result: " NUM1.Explanation
In the Procedure Division, code can be organized into SECTIONS. A section is a collection of one or more paragraphs. Sections provide a higher level of grouping than paragraphs, allowing you to modularize your code into logical units like initialization, processing, and cleanup sections.
The PERFORM statement is used to transfer control to a section (or paragraph) and return when it completes. This is similar to calling a void function in other languages. In this code example, when you PERFORM CALCULATION-SECTION, the program jumps to that section, executes all instructions within it, and then returns to the line immediately following the PERFORM statement.
Using sections is considered a best practice for structuring large COBOL programs. It makes the code easier to read and navigate. A section ends when the next section begins, or at the end of the program. It is important to manage control flow carefully (e.g., using STOP RUN) to prevent the program from accidentally falling through into the next section.