Why are there alternative tokens in C++?
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Possible Duplicate:
Why are there digraphs in C and C++?
What does the C ??!??! operator do?!
在C++中，对于[]和{}，还有其他的代币。
例如，以下代码编译：
1 2 3 4 | %:include <stdio.h> int main() <% printf("Hello World!"); } |
我考虑了一会儿，但没想到有什么适用性，这有什么逻辑上的原因吗？
他们是C的宿醉，真的。有些C的实现中并不是所有字符都可用(例如一些没有方括号的EBCDIC变体)。
C99基本原理文件第
Trigraph sequences were introduced in C89 as alternate spellings of some characters to allow the implementation of C in character sets which do not provide a sufficient number of non-alphabetic graphics.
The characters in the ASCII repertoire used by C and absent from the ISO/IEC 646 invariant repertoire are
# ,[ ,] ,{ ,} ,\ ,| ,~ , and^