换码顺序？在c ++ [英] Escape sequence for ? in c++

问题描述

我在查看c ++中字符串中的字符的转义序列，我注意到有一个问号的转义序列。有人能告诉我为什么会这样吗？它只是似乎有点奇怪，我不知道什么？在字符串中。感谢。

I was looking at the escape sequences for characters in strings in c++ and I noticed there is an escape sequence for a question mark. Can someone tell me why this is? It just seems a little odd and I can't figure out what ? does in a string. Thanks.

推荐答案

这是为了避免将问号误解为 trigraph 。

It's to keep a question mark from getting misinterpreted as part of a trigraph.

例如，在

"What??!"

??将被解释为 | 字符，因此，您必须如下转义问号：

The "??! would be interpreted as the | character. So, you have to escape the question marks as follows:

"What\?\?!"

http://msdn.microsoft.com/en-us/library/bt0y4awe%28VS.80%29.aspx

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