Use a 'goto' in a switch?

Question

I've seen a suggested coding standard that reads Never use goto unless in a switch statement fall-through.

I don't follow. What exactly would this 'exception' case look like, that justifies a goto?

Answer 1

This construct is illegal in C#:

switch (variable) {
   case 2: 
       Console.WriteLine("variable is >= 2");
   case 1:
       Console.WriteLine("variable is >= 1");
}

In C++, it would run both lines if variable = 2. It may be intentional but it's too easy to forget break; at the end of the first case label. For this reason, they have made it illegal in C#. To mimic the fall through behavior, you will have to explicitly use goto to express your intention:

switch (variable) {
   case 2: 
       Console.WriteLine("variable is >= 2");
       goto case 1;
   case 1:
       Console.WriteLine("variable is >= 1");
       break;
}

_{That said, there are a few cases where goto is actually a good solution for the problem. Never shut down your brain with "never use something" rules. If it were 100% useless, it wouldn't have existed in the language in the first place. Don't use goto is a guideline; it's not a law.}