Welcome to OGeek Q&A Community for programmer and developer-Open, Learning and Share
Welcome To Ask or Share your Answers For Others

Categories

0 votes
534 views
in Technique[技术] by (71.8m points)

c# - Why do you need to put break after the last label of a switch statement?

Surely the compiler knows that it's the last label of the switch statement?

See Question&Answers more detail:os

与恶龙缠斗过久,自身亦成为恶龙;凝视深渊过久,深渊将回以凝视…
Welcome To Ask or Share your Answers For Others

1 Reply

0 votes
by (71.8m points)

It's because in C++ this is what happens:

switch(a)
{
     case 1:
        // do stuff

     case 2:
        // do other stuff
}

If a is 1, then - according to C++ rules - both "do stuff" and "do other stuff" would happen. So that C++ programmers coming to C# do not get tripped up (and to make code clearer all 'round), C# requires that you explicitly specify whether you want to break or fall through to a different label.

Now, as for why you need the break on the last block, that's a simple matter of consistency. It also make re factoring easier: if you move the cases around, you don't suddenly end up with errors because of a missing break statement. Also, what happens when you want to add another label, etc, etc.


与恶龙缠斗过久,自身亦成为恶龙;凝视深渊过久,深渊将回以凝视…
OGeek|极客中国-欢迎来到极客的世界,一个免费开放的程序员编程交流平台!开放,进步,分享!让技术改变生活,让极客改变未来! Welcome to OGeek Q&A Community for programmer and developer-Open, Learning and Share
Click Here to Ask a Question

...