COBOL IF Statement: Mastering COBOL If Statements with Syntax and Examples.

COBOL IF Statements with Example.

COBOL IF Statement is one of the important elements in the Cobol programming language. IF Statement in COBOL is a powerful construct that allows developers to make decisions based on different conditions. It is used to test one or more conditions and execute a block of code based on the result.

In this article, we will explore the different variants of COBOL IF Statements, their syntax, and examples. The article precisely talks about the COBOL IF Statement with Continue Clause, COBOL IF Statement with Next Sentence Clause, and COBOL IF statement with multiple conditions. So, without wasting time let's deep dive into the IF statement of COBOL.

COBOL IF Statement - Introduction.

If statement in COBOL is an essential part of the programming because it facilitates the conditional execution of the code based on the evaluation of a specified condition. It means that the program can take different paths or actions depending on whether a condition is true or false, allowing for more complex and dynamic programming logic. The following diagram illustrates the importance of the if statement in COBOL.

COBOL IF END-IF Statement.

Note: It is recommended that you should never use nested if's more than 3 levels deep because it would degrade the performance of the COBOL program. In such a scenario, you must consider using COBOL Evaluate statements.

Importance of COBOL IF Statement in Programming.

The COBOL If Statement offers a high degree of flexibility, as it can be combined with other statements and functions to provide more complex program logic. This can be especially useful in large and complex programs where different conditions may need to be evaluated at different stages. Another important aspect of the COBOL IF statement is that it helps in skipping unnecessary steps if a certain condition is not met. This can result in more efficient and streamlined code, which is easier to maintain.

Explanation of the syntax of COBOL If Statement.

The format of the IF Statement in COBOL is pretty simple and straightforward. In fact, COBOL If conditions have various formats and you can use these different variants as per business requirements. 

Basic Format:  IF condition [THEN] imperative statements
                  ELSE imperative statements
               END-IF

Note: An imperative statement as opposed to a conditional statement, is one that performs an operation regardless of any existing conditions.

NESTED IFs Statement in COBOL: The THEN and ELSE parts of an IF statement can contain other IF statements. The included IF statements in turn may also contain other IF statements. Such inclusion of one or more IF statements within the scope of an IF statement is called nesting of IF statements.

Format:  IF condition [THEN] imperative statements
            ELSE imperative statements
                 IF Condition
                    imperative statements
                 END-IF
         END-IF.

The following example illustrates the IF-ELSE-END-IF Statement in COBOL.

COBOL IF END-IF Statement Example.

Note: Always indent statements with the IF instruction to make programs easier to read and debug. 

Now, let's discuss each variant of COBOL If Statements. 

IF-THEN-ELSE in COBOL

The most basic form of the COBOL IF statement is the IF-THEN-ELSE structure. This structure performs operations based on a single condition. The format of this structure is as follows:

IF condition [THEN] imperative statements
   ELSE imperative statements

END-IF

Here, "condition" is a logical expression that evaluates to either TRUE or FALSE. If the condition is true, then the imperative statements under "THEN" are executed. If the condition is false, then the imperative statements under "ELSE" are executed. The "THEN" and "ELSE" parts of this structure are optional.

Nested IFs in COBOL.

The IF-THEN-ELSE structure can contain other IF statements, which are called nested IFs. This allows for more complex selection structures to be created. Here is the format of a nested IF structure:

IF condition [THEN]

   imperative statements

ELSE imperative statements

IF Condition

   imperative statements

END-IF

END-IF.

In this structure, the "ELSE" part can contain another IF statement. If the condition under "ELSE" is true, then the imperative statements under the nested IF statement are executed. The nested IF statement can also contain another IF statement, and so on. This is known as the nesting of IF statements.

COBOL IF Statement with Multiple Conditions.

The IF-THEN-ELSE structure can also handle multiple conditions, which are connected with logical operators such as AND and OR. Here is the format of the COBOL IF statement with multiple conditions:

IF condition-1 AND/OR condition-2 [THEN] 

    imperative statements

ELSE 

    imperative statements

END-IF

In this structure, "condition-1" and "condition-2" are logical expressions that are connected by the AND or OR operator. If both conditions are true, then the imperative statements under "THEN" are executed. If either condition is false, then the imperative statements under "ELSE" are executed.

COBOL IF Statement with Multiple Values.

In addition to multiple conditions, the COBOL IF statement can also handle multiple values. Here is the format of the COBOL IF statement with multiple values:

IF identifier-1 = value-1, value-2,...value-n [THEN] 

   imperative statements

ELSE 

   imperative statements

END-IF.

In this structure, "identifier-1" is a variable that is compared to a list of values. If the value of "identifier-1" matches any of the values in the list, then the imperative statements under "THEN" are executed. Otherwise, the imperative statements under "ELSE" are executed.

COBOL IF Statement with NEXT SENTENCE

The COBOL IF statement can also be used with the NEXT SENTENCE keyword, which skips the current statement and moves on to the next one after the period. Here is the format of the COBOL IF statement with the NEXT SENTENCE:

IF condition [THEN]

   NEXT SENTENCE | imperative statements

.

In this structure, if the condition is true, then the NEXT SENTENCE keyword is used to skip the current statement and move on to the next one. This can be useful for improving the readability of the code.

COBOL IF Statement with CONTINUE

The COBOL IF statement can also be used with the CONTINUE keyword, which skips the current statement and moves on to the next executable statement after the END-IF. Here is the format of the COBOL IF statement with the CONTINUE:

IF condition [THEN]

   CONTINUE | imperative statements

END-IF.

In this structure, if the condition is true, then the Continue keyword is used to skip the current statement and move on to the next one. This can be useful for improving the readability of the code.

Youtube Tutorial: COBOL Control Statements. 

The following Youtube tutorial video clearly explains various COBOL Control statements.   

Summary. 

In summary, COBOL If Statements are an important construct in programming that allows for the conditional execution of code based on specified conditions. They can help to reduce code complexity, improve efficiency, and offer a high level of flexibility for more complex programming logic.