英文:
Why actually the fall through happens
问题
我已经搜索了这个特定的问题很多次，但没有找到任何合适的答案。到处都只是关于当出现"fall through"情况时的解释，他们没有描述我的问题。有谁可以帮帮我吗？
众所周知，如果没有break语句，switch case会进入"fall through"条件。但我想问的是，如果switch case按照case逐个检查值，假设它正在检查第二个case，并且第二个case中没有break，那么根据语言协议，它必须会继续执行下一个case。但既然switch会检查和比较各个case，为什么编译器不会再次检查下一个case呢？我的意思是，为什么它会在不检查case是否相等的情况下运行下一个case的代码块呢？
英文:
I have searched this particular question a lot but didn't find any appropriate answers for it. Everywhere it's only written just only about when fall through happens , they haven't described my issue. Can anyone pls help me .
As we all know that switch case goes to fall through condition if there is no break statement. But i wanna ask that if switch case check value by cases then , if suppose it is checking the second case and there is no break in the second case , then according to language protocols it must falls through but as switch checks and compare the cases then why shouldn't the compiler again checks the next case , i mean then why it runs the block of next case without checking the case equality.
答案1
得分: 0
我认为这个问题非常有趣。
仅在执行流程进入一个 case 时才执行一次等式比较。
不需要使用 break，因为它允许控制执行流程。
在许多 switch/case 的情况下，您可能希望先执行 case B，然后执行所有后续 case（case C，case D 等）。
因此，这个限制是有意设计的。
实际上这并不是一种限制。
它在使用这个语句时提供了一些灵活性。
英文:
I think this question is pretty interesting.
Comparison for equality is done only once, until the execution flow enters a case.
A break is not necessary because it allows to control the execution flow.
There are a lot of situations with switch/case when you'd like to execute case B and after that you'd like to execute all following cases (case C, case D, etc).
So, this limitation is by design.
Actually it's not a limitation.
It gives you some flexibility in using this statement.
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