user-0 提问: 读书遇到一个C语言问题，有些不理解，希望得到帮助。

回复:
user: user-1
content: 引用 4 楼 iojkl0987 的回复:[quote=引用 3 楼 u010165006 的回复:] 楼主这本是什么书？ 什么情况下需要这么用呢？  C.Primer.Plus 第3.43使用字符char类型里的 一、声明 char 类型变量[/quote] 老外的书讲了很多不常用的细节

user: user-0
content: 引用 4 楼 iojkl0987 的回复:[quote=引用 3 楼 u010165006 的回复:] 楼主这本是什么书？ 什么情况下需要这么用呢？  C.Primer.Plus 第3.43使用字符char类型里的 一、声明 char 类型变量[/quote]  第五版

user: user-0
content: 引用 3 楼 u010165006 的回复:楼主这本是什么书？ 什么情况下需要这么用呢？  C.Primer.Plus 第3.43使用字符char类型里的 一、声明 char 类型变量

user: user-1
content: 楼主这本是什么书？ 什么情况下需要这么用呢？

user: user-2
content: char ch='FATE', 最后得到'E' 每个字符8位, 4个刚好32位, 但现在这个已经由实现定义,并不能保证一定能够得到'E',慎用吧

user: user-3
content: 理解和讨论之前请先学会如何观察！  计算机组成原理→DOS命令→汇编语言→C语言（不包括C++）、代码书写规范→数据结构、编译原理、操作系统→计算机网络、数据库原理、正则表达式→其它语言（包括C++）、架构……  对学习编程者的忠告： 多用小脑和手，少用大脑、眼睛和嘴，会更快地学会编程！ 眼过千遍不如手过一遍！ 书看千行不如手敲一行！ 手敲千行不如单步一行！ 单步源代码千行不如单步Debug版对应汇编一行！ 单步Debug版对应汇编千行不如单步Release版对应汇编一行！  VC调试时按Alt+8、Alt+7、Alt+6和Alt+5,打开汇编窗口、堆栈窗口、内存窗口和寄存器窗口看每句C对应的汇编、单步执行并观察相应堆栈、内存和寄存器变化，这样过一遍不就啥都明白了吗。 对VC来说，所谓‘调试时’就是编译连接通过以后，按F10或F11键单步执行一步以后的时候，或者在某行按F9设了断点后按F5执行停在该断点处的时候。 （Turbo C或Borland C用Turbo Debugger调试,Linux或Unix下用GDB调试时,看每句C对应的汇编并单步执行观察相应内存和寄存器变化。）  电脑内存或文件内容只是一个一维二进制字节数组及其对应的二进制地址； 人脑才将电脑内存或文件内容中的这个一维二进制字节数组及其对应的二进制地址的某些部分看成是整数、有符号数/无符号数、浮点数、复数、英文字母、阿拉伯数字、中文/韩文/法文……字符/字符串、汇编指令、函数、函数参数、堆、栈、数组、指针、数组指针、指针数组、数组的数组、指针的指针、二维数组、字符点阵、字符笔画的坐标、黑白二值图片、灰度图片、彩色图片、录音、视频、指纹信息、身份证信息……  推荐使用WinHex软件查看硬盘或文件或内存中的原始字节内容。  C++ Character Constants Character constants are one or more members of the “source character set,” the character set in which a program is written, surrounded by single quotation marks ('). They are used to represent characters in the “execution character set,” the character set on the machine where the program executes.  Microsoft Specific   For Microsoft C++, the source and execution character sets are both ASCII.  END Microsoft Specific  There are three kinds of character constants:   Normal character constants   Multicharacter constants   Wide-character constants  Note   Use wide-character constants in place of multicharacter constants to ensure portability.  Character constants are specified as one or more characters enclosed in single quotation marks. For example:  char ch = 'x';          // Specify normal character constant. int mbch = 'ab';        // Specify system-dependent                         //  multicharacter constant. wchar_t wcch = L'ab';   // Specify wide-character constant.  Note that mbch is of type int. If it were declared as type char, the second byte would not be retained. A multicharacter constant has four meaningful characters; specifying more than four generates an error message.  Syntax  character-constant :  'c-char-sequence' L'c-char-sequence'  c-char-sequence :  c-char c-char-sequence c-char  c-char :  any member of the source character set except the single quotation mark ('), backslash (\), or newline character escape-sequence  escape-sequence :  simple-escape-sequence octal-escape-sequence hexadecimal-escape-sequence  simple-escape-sequence : one of  \' \" \? \\ \a \b \f \n \r \t \v  octal-escape-sequence :  \octal-digit \octal-digit octal-digit \octal-digit octal-digit octal-digit  hexadecimal-escape-sequence :  \xhexadecimal-digit hexadecimal-escape-sequence hexadecimal-digit  Microsoft C++ supports normal, multicharacter, and wide-character constants. Use wide-character constants to specify members of the extended execution character set (for example, to support an international application). Normal character constants have type char, multicharacter constants have type int, and wide-character constants have type wchar_t. (The type wchar_t is defined in the standard include files STDDEF.H, STDLIB.H, and STRING.H. The wide-character functions, however, are prototyped only in STDLIB.H.)  The only difference in specification between normal and wide-character constants is that wide-character constants are preceded by the letter L. For example:  char schar = 'x';               // Normal character constant wchar_t wchar = L'\x81\x19';    // Wide-character constant  Table 1.2 shows reserved or nongraphic characters that are system dependent or not allowed within character constants. These characters should be represented with escape sequences.  Table 1.2   C++ Reserved or Nongraphic Characters  Character ASCII  Representation ASCII  Value Escape Sequence  Newline NL (LF) 10 or 0x0a \n  Horizontal tab HT 9 \t  Vertical tab VT 11 or 0x0b \v  Backspace BS 8 \b  Carriage return CR 13 or 0x0d \r  Formfeed FF 12 or 0x0c \f  Alert BEL 7 \a  Backslash \ 92 or 0x5c \\  Question mark ? 63 or 0x3f \?  Single quotation mark ' 39 or 0x27 \'  Double quotation mark " 34 or 0x22 \"  Octal number ooo — \ooo  Hexadecimal number hhh — \xhhh  Null character NUL 0 \0    If the character following the backslash does not specify a legal escape sequence, the result is implementation defined. In Microsoft C++, the character following the backslash is taken literally, as though the escape were not present, and a level 1 warning (“unrecognized character escape sequence”) is issued.  Octal escape sequences, specified in the form \ooo, consist of a backslash and one, two, or three octal characters. Hexadecimal escape sequences, specified in the form \xhhh, consist of the characters \x followed by a sequence of hexadecimal digits. Unlike octal escape constants, there is no limit on the number of hexadecimal digits in an escape sequence.  Octal escape sequences are terminated by the first character that is not an octal digit, or when three characters are seen. For example:  wchar_t och = L'\076a';  // Sequence terminates at a char    ch = '\233';     // Sequence terminates after 3 characters  Similarly, hexadecimal escape sequences terminate at the first character that is not a hexadecimal digit. Because hexadecimal digits include the letters a through f (and A through F), make sure the escape sequence terminates at the intended digit.  Because the single quotation mark (') encloses character constants, use the escape sequence \' to represent enclosed single quotation marks. The double quotation mark (") can be represented without an escape sequence. The backslash character (\) is a line-continuation character when placed at the end of a line. If you want a backslash character to appear within a character constant, you must type two backslashes in a row (\\). (SeePhases of Translation in the Preprocessor Reference for more information about line continuation.)