Evaluate in cobol with multiple condition – The EVALUATE statement in COBOL provides a powerful mechanism for evaluating multiple conditions in a concise and efficient manner. This article delves into the syntax, usage, and best practices of the EVALUATE statement, empowering programmers to harness its full potential in their COBOL applications.

The EVALUATE statement enables the evaluation of multiple conditions, allowing for complex decision-making logic to be implemented in a structured and readable way. By leveraging the WHEN and OTHERWISE clauses, programmers can define specific conditions and the actions to be taken when those conditions are met or not met, respectively.

Introduction

The EVALUATE statement in COBOL is a powerful tool for evaluating multiple conditions and performing specific actions based on the results of the evaluation. It provides a concise and efficient way to handle complex decision-making scenarios, reducing the need for nested IF statements and improving code readability.

Syntax of the EVALUATE Statement

The syntax of the EVALUATE statement is as follows:

• EVALUATE identifier1, identifier2, …, identifiern
• WHEN condition1 THEN statement-list1
• WHEN condition2 THEN statement-list2
• …
• WHEN conditionn THEN statement-listn
• OTHERWISE statement-list

The identifiers represent the variables or expressions being evaluated, and the conditions specify the criteria for each WHEN clause. The statement-list associated with each WHEN clause contains the actions to be performed if the corresponding condition is met. The OTHERWISE clause is optional and specifies the actions to be performed if none of the WHEN conditions are met.

Using the EVALUATE Statement with Multiple Conditions

To evaluate multiple conditions using the EVALUATE statement, you specify each condition in a separate WHEN clause. The conditions can be simple or complex, and they can use logical operators (AND, OR, NOT) to combine multiple conditions. For example:

EVALUATE age
WHEN age > 18 AND age < 65 THEN
   DISPLAY "You are an adult."
WHEN age <= 18 THEN
   DISPLAY "You are a child."
WHEN age >= 65 THEN
   DISPLAY "You are a senior citizen."
OTHERWISE

  DISPLAY "Invalid age." 

In this example, the EVALUATE statement evaluates the value of the age variable and performs different actions based on the result. If the age is greater than 18 and less than 65, the statement displays “You are an adult.”

If the age is less than or equal to 18, the statement displays “You are a child.” If the age is greater than or equal to 65, the statement displays “You are a senior citizen.” If none of these conditions are met, the OTHERWISE clause displays “Invalid age.”

Using the OTHERWISE Clause

The OTHERWISE clause in the EVALUATE statement is used to handle cases where none of the WHEN conditions are met. It is optional, but it is recommended to include an OTHERWISE clause to ensure that all possible cases are handled.

For example:

EVALUATE grade
WHEN grade = "A" THEN
   DISPLAY "Excellent"
WHEN grade = "B" THEN
   DISPLAY "Good"
WHEN grade = "C" THEN
   DISPLAY "Average"
OTHERWISE
   DISPLAY "Invalid grade" 

In this example, the EVALUATE statement evaluates the value of the grade variable and performs different actions based on the result.

If the grade is “A,” the statement displays “Excellent.” If the grade is “B,” the statement displays “Good.” If the grade is “C,” the statement displays “Average.” If the grade is anything other than “A,” “B,” or “C,” the OTHERWISE clause displays “Invalid grade.”

Nesting EVALUATE Statements: Evaluate In Cobol With Multiple Condition

EVALUATE statements can be nested within other EVALUATE statements to create complex decision-making structures. This can be useful for handling scenarios where the outcome of one evaluation depends on the result of another evaluation. For example:

EVALUATE status
WHEN status = "active" THEN
   EVALUATE role
   WHEN role = "admin" THEN
      DISPLAY "You are an administrator."
   WHEN role = "user" THEN
      DISPLAY "You are a user."

  OTHERWISE
      DISPLAY "Invalid role"
OTHERWISE
   DISPLAY "Your account is inactive." 

In this example, the outer EVALUATE statement evaluates the status variable and performs different actions based on the result. If the status is “active,” the inner EVALUATE statement evaluates the role variable and performs different actions based on the result.

If the status is anything other than “active,” the OTHERWISE clause displays “Your account is inactive.”

Tips for Using the EVALUATE Statement Effectively

Here are some tips for using the EVALUATE statement effectively:

• Use the EVALUATE statement when you need to evaluate multiple conditions and perform different actions based on the results.
• Use logical operators (AND, OR, NOT) to combine multiple conditions in a single WHEN clause.
• Use the OTHERWISE clause to handle cases where none of the WHEN conditions are met.
• Nest EVALUATE statements to create complex decision-making structures.
• Avoid using too many nested EVALUATE statements, as this can make your code difficult to read and maintain.

Frequently Asked Questions

What is the purpose of the EVALUATE statement in COBOL?

The EVALUATE statement in COBOL allows programmers to evaluate multiple conditions and execute specific actions based on the evaluation results.

How do I specify multiple conditions in the EVALUATE statement?

Multiple conditions can be specified using the WHEN clause, where each WHEN clause represents a specific condition. If the condition is met, the corresponding action is executed.

What is the role of the OTHERWISE clause in the EVALUATE statement?

The OTHERWISE clause provides a default action to be executed when none of the WHEN conditions are met.

Can EVALUATE statements be nested within other EVALUATE statements?

Yes, EVALUATE statements can be nested within other EVALUATE statements, allowing for more complex decision-making logic.