COBOL Programming Constructs
COBOL Programming Constructs are used to control the flow of execution in COBOL programs. They include conditionals, loops, and subroutines, among others. Here's an overview of each programming construct and some code examples:
- Conditionals: Conditionals are used to make decisions based on the value of a condition. COBOL supports several types of conditionals, including IF statements, ELSE statements, and CASE statements. For example:
IF AGE > 18
DISPLAY "You are an adult."
ELSE
DISPLAY "You are a minor."
END-IF.
In this example, the IF statement checks if the value of the variable AGE is greater than 18. If it is, the message "You are an adult." is displayed; otherwise, the message "You are a minor." is displayed.
- Loops: Loops are used to execute a block of code repeatedly. COBOL supports several types of loops, including DO WHILE, DO UNTIL, and PERFORM UNTIL. For example:
PERFORM VARYING I FROM 1 BY 1 UNTIL I > 10
DISPLAY I
END-PERFORM.
In this example, the PERFORM loop executes the DISPLAY statement 10 times, with the value of the variable I increasing from 1 to 10.
- Subroutines: Subroutines are used to break up large programs into smaller, more manageable pieces. COBOL supports the use of subroutines through the PERFORM statement. For example:
PERFORM MY-SUBROUTINE.
MY-SUBROUTINE.
DISPLAY "Hello, world!"
EXIT.
In this example, the PERFORM statement calls the MY-SUBROUTINE subroutine, which displays the message "Hello, world!" and then exits.
In addition to these programming constructs, COBOL also supports other constructs such as GO TO statements, which allow for non-linear flow of execution, and the EVALUATE statement, which can be used to simplify complex decision-making logic.
Overall, understanding the different programming constructs available in COBOL is essential when working with COBOL programs as they are used extensively to control the flow of execution within these programs.
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