Use a Meaningful Default Value

Oct 13, 2025 by talynt.org 90 views

Missing Default Cases in Switch Statements (Display Functions)

Introduction

In software development, switch statements are a common way to handle different cases based on the value of a variable. However, it's essential to include default cases in switch statements to ensure robustness and prevent unexpected behavior. In this article, we'll discuss the importance of including default cases in switch statements, particularly in display functions.

The Issue

In the display_details() methods for both FullTime and PartTime classes, the switch statements for m_role and m_status do not include a default case. Although all enum values are covered, adding a default case can improve the robustness of the code.

// FullTime class
void display_details() {
    switch (m_role) {
        case EmployeeRole::intern:   tmp = "Intern"; break;
        case EmployeeRole::junior:   tmp = "Junior"; break;
        case EmployeeRole::middle:   tmp = "Middle"; break;
        case EmployeeRole::senior:   tmp = "Senior"; break;
    }
    // ...
}

// PartTime class
void display_details() {
    switch (m_status) {
        case EmployeeStatus::active:   tmp = "Active"; break;
        case EmployeeStatus::inactive:   tmp = "Inactive"; break;
        case EmployeeStatus::suspended:   tmp = "Suspended"; break;
    }
    // ...
}

The Fix

To fix this issue, we need to add a default case to both switch statements. The default case should set the output string to something like "Unknown" for both role and status switches.

// FullTime class
void display_details() {
    switch (m_role) {
        case EmployeeRole::intern:   tmp = "Intern"; break;
        case EmployeeRole::junior:   tmp = "Junior"; break;
        case EmployeeRole::middle:   tmp = "Middle"; break;
        case EmployeeRole::senior:   tmp = "Senior"; break;
        default:                     tmp = "Unknown"; break;
    }
    // ...
}

// PartTime class
void display_details() {
    switch (m_status) {
        case EmployeeStatus::active:   tmp = "Active"; break;
        case EmployeeStatus::inactive:   tmp = "Inactive"; break;
        case EmployeeStatus::suspended:   tmp = "Suspended"; break;
        default:                     tmp = "Unknown"; break;
    }
    // ...
}

Benefits of Including Default Cases

Including default cases in switch statements provides several benefits:

Improved Robustness: By including a default case, we can ensure that the code handles unexpected values or cases that are not explicitly covered by the switch statement.
Reduced Bugs: Without a default case, the code may produce unexpected behavior or crashes when encountering an unexpected value. Including a default case can help prevent such bugs.
Easier Debugging: With a default case, it's easier to identify and debug issues related to unexpected values or cases.

Best Practices for Including Default Cases

When including default cases in switch statements, follow these best practices:

Use a Meaningful Default Value: Choose a default value that makes sense in the context of the code. In the example above, we used "Unknown" as the default value.
Document the Default Case: Document the default case in the code to ensure that other developers understand its purpose and behavior.
Test the Default Case: Test the default case to ensure that it behaves as expected and doesn't introduce any bugs.

Conclusion

In conclusion, including default cases in switch statements is essential for ensuring robustness and preventing unexpected behavior. By following the best practices outlined in this article, developers can write more robust and maintainable code. Remember to always include a default case in switch statements, especially in display functions, to ensure that the code handles unexpected values or cases.
Missing Default Cases in Switch Statements (Display Functions) - Q&A

Introduction

In our previous article, we discussed the importance of including default cases in switch statements, particularly in display functions. In this article, we'll answer some frequently asked questions (FAQs) related to missing default cases in switch statements.

Q1: Why is it necessary to include a default case in a switch statement?

A1: Including a default case in a switch statement ensures that the code handles unexpected values or cases that are not explicitly covered by the switch statement. This improves the robustness of the code and prevents unexpected behavior or crashes.

Q2: What happens if I don't include a default case in a switch statement?

A2: If you don't include a default case in a switch statement, the code may produce unexpected behavior or crashes when encountering an unexpected value. This can lead to bugs and make debugging more challenging.

Q3: How do I choose a meaningful default value?

A3: When choosing a default value, consider the context of the code and the expected behavior. In the example above, we used "Unknown" as the default value. You can choose a default value that makes sense in your specific use case.

Q4: Do I need to include a default case in every switch statement?

A4: While it's not necessary to include a default case in every switch statement, it's a good practice to include one whenever possible. This ensures that the code handles unexpected values or cases and improves its robustness.

Q5: Can I use a throw statement instead of a default case?

A5: No, you should not use a throw statement instead of a default case. A throw statement is used to throw an exception, whereas a default case is used to handle unexpected values or cases. Using a throw statement in a default case can lead to unexpected behavior and make debugging more challenging.

Q6: How do I document the default case in my code?

A6: You can document the default case in your code by including a comment that explains its purpose and behavior. For example:

// Default case: handle unexpected values or cases
default:
    // Log an error message or handle the unexpected value
    std::cerr << "Unexpected value: " << m_role << std::endl;
    break;

Q7: Can I use a default case in a switch statement with multiple cases?

A7: Yes, you can use a default case in a switch statement with multiple cases. The default case will be executed if none of the cases match the value of the variable.

Q8: How do I test the default case in my code?

A8: You can test the default case in your code by using a debugger or by writing test cases that cover the default case. For example, you can write a test case that sets the variable to an unexpected value and verifies that the default case is executed.

Q9: Can I use a default case in a switch statement with a variable number of cases?

A9: Yes, you can use a default case in a switch statement with a variable number of cases. The default case will be executed if none of the cases match the value of the variable.

Q10: How do I ensure that my code handles unexpected values or cases?

A10: To ensure that your code handles unexpected values or cases, follow these best practices:

Include a default case in switch statements.
Document the default case in your code.
Test the default case in your code.
Use a debugger or write test cases to verify that the default case is executed.

By following these best practices, you can ensure that your code handles unexpected values or cases and improves its robustness.