Goto for Switching Logic (Anti-Pattern)

This snippet showcases an anti-pattern using goto to mimic switch-case behavior. While technically functional, this approach is strongly discouraged due to poor readability and maintainability.

Code Demonstration

This code attempts to simulate a switch statement using if-else conditions and goto statements. Based on the value of the choice variable, the code jumps to the corresponding case label. Each case then uses another goto statement to jump to the end label to avoid falling through to the next case. This is a complex and hard-to-read approach and should be avoided in favor of a standard switch statement.

using System;

public class GotoSwitchExample
{
    public static void Main(string[] args)
    {
        int choice = 2;

        if (choice == 1)
        {
            goto case1;
        }
        else if (choice == 2)
        {
            goto case2;
        }
        else
        {
            goto defaultCase;
        }

    case1:
        Console.WriteLine("You chose option 1.");
        goto end;

    case2:
        Console.WriteLine("You chose option 2.");
        goto end;

    defaultCase:
        Console.WriteLine("Invalid choice.");
        goto end;

    end:
        Console.WriteLine("Program finished.");
    }
}

Why This Is an Anti-Pattern

• Poor Readability: The control flow is obscured by the numerous goto statements. It's difficult to quickly understand the program's logic.
• Maintainability Issues: Adding or modifying cases becomes error-prone. Forgetting to add a goto end; statement can lead to unintended fall-through behavior.
• Redundancy: The if-else chain and the separate goto statements for each case are redundant and add unnecessary complexity.

The Preferred Approach: Switch Statement

The switch statement provides a clear and concise way to handle multiple cases based on the value of a variable. It automatically prevents fall-through behavior (unless explicitly intended) and is much easier to read and maintain than the goto-based approach. The break statement is used to exit the switch block after executing the code for the matching case.

using System;

public class SwitchExample
{
    public static void Main(string[] args)
    {
        int choice = 2;

        switch (choice)
        {
            case 1:
                Console.WriteLine("You chose option 1.");
                break;
            case 2:
                Console.WriteLine("You chose option 2.");
                break;
            default:
                Console.WriteLine("Invalid choice.");
                break;
        }

        Console.WriteLine("Program finished.");
    }
}

Best Practices

Always favor the switch statement over goto when implementing branching logic based on multiple conditions. The switch statement provides better structure, readability, and maintainability.