允许使用多个字符的C ++ Char初始化 [英] C++ Char Initialization Allowed With Multiple Characters

问题描述

在通过阅读本书学习C ++的过程中，我看到了（对我而言）这奇怪的代码行。

During learning about C++ by reading a book I have seen this (for me) strange line of code.

char ch（‘AB’）; //或者char ch ='AB';

这对我来说很奇怪，因为我不知道您可以分配给 char 多个字母而没有任何异常。

It is strange for me because I don't get that you can assign to a char multiple "letters" without getting any exception.

cout << "Characters in ch: " << ch << endl; // Output B

为什么这样做？它在内部如何运作？

Why does this work? And how is it working internally? Is it only saving the last character and ignoring the other ones?

推荐答案

它被称为 多字符文字 ，它们是完全有效的C ++：

It's called a multicharacter literal which are completely valid C++:

多字符文字，例如'AB'，具有类型 int 和实现定义的值。

Multicharacter literal, e.g. 'AB', has type int and implementation-defined value.

[...]

许多多字符文字的实现都使用文字中每个char的值以大端顺序对初始化的连续整数字节进行初始化，例如'\1\2\3\4'的值是 0x01020304 。

Many implementations of multicharacter literals use the values of each char in the literal to initialize successive bytes of the resulting integer, in big-endian order, e.g. the value of '\1\2\3\4' is 0x01020304.

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