回退符:\b 怎么输入？

DeepBlueTears 2011-12-25 12:40:45

刚开始学C，正在看《C程序设计语言》，这是练习1-10的代码：



#include <stdio.h>

/* 编写一个将输入复制到输出的程序，并将其中的制表符替换为 \t ，

  把回退符替换为 \b ，把反斜杠替换为 \\ 。 这样可以将制表符

  和回退符以可见的方式显示出来。

 */

main()

{

  int c;



  while ((c = getchar()) != EOF){

    if (c == '\t')

        printf("\\t");

    if (c == '\b')

        printf("\\b");

    if (c == '\\')

        printf("\\\\");

    if (c != '\t')

      if (c != '\b')

        if (c != '\\')

          putchar(c);

  }

}

想问一下各位大侠，在win7系统下，回退符怎么输入？

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带着儿子打酱油 2013-11-27

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引用 7 楼 Saleayas 的回复:

Ctrl-Z 是文本流控制符。这个控制符只有在流控制的时候才有效。也就是说在 getchar()、ReadFile(...) 的时候才有效。鱼和熊掌的关系。

是不是可以这样理解那： getchar（）时用 Backspace的时候直接在缓冲区处理了；相当于是对缓冲区的处理字符，不能被缓冲区记录，getch函数的时候backspace不能处理getch的缓冲区

vanguards 2011-12-25

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1楼应该对吧

缺媳妇的郝 2011-12-25

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mark,也不知道，求大牛……

handoudouhao 2011-12-25

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就是键盘上的backspace键，退格键

DeepBlueTears 2011-12-25

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[Quote=引用 7 楼 saleayas 的回复:]
Ctrl-Z 是文本流控制符。
这个控制符只有在流控制的时候才有效。
也就是说在 getchar()、ReadFile(...) 的时候才有效。

鱼和熊掌的关系。
[/Quote]
是这样啊，谢谢。

Saleayas 2011-12-25

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Ctrl-Z 是文本流控制符。
这个控制符只有在流控制的时候才有效。
也就是说在 getchar()、ReadFile(...) 的时候才有效。

鱼和熊掌的关系。

DeepBlueTears 2011-12-25

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[Quote=引用 5 楼 saleayas 的回复:]
用 <conio.h> 下面的
_getch()

替换
getchar()

因为 getchar() 函数输入流先处理了。
[/Quote]
谢谢，'\b' 看到了，可是输入EOF(Ctrl+z)后回车退不出程序了…………只能Ctrl+c中断
输入ctrl+Z时不再像使用getchar时那样显示^Z，而是显示一个箭头→

Saleayas 2011-12-25

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用 <conio.h> 下面的
_getch()

替换
getchar()

因为 getchar() 函数输入流先处理了。

DeepBlueTears 2011-12-25

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[Quote=引用 1 楼 handoudouhao 的回复:]
就是键盘上的backspace键，退格键
[/Quote]
额，我试过了，按backspace，然后回车，没有看见输出“\b”

The C programming Language 第二版英文版內容列表 Table of Contents Preface.......................................................... Preface to the first edition..................................... Introduction..................................................... Chapter 1 - A Tutorial Introduction.............................. 1.1 Getting Started................................ 1.2 Variables and Arithmetic Expressions........... 1.3 The for statement.............................. 1.4 Symbolic Constants............................. 1.5 Character Input and Output..................... 1.5.1 File Copying.......................... 1.5.2 Character Counting.................... 1.5.3 Line Counting......................... 1.5.4 Word Counting......................... 1.6 Arrays......................................... 1.7 Functions...................................... 1.8 Arguments - Call by Value...................... 1.9 Character Arrays............................... 1.10 External Variables and Scope.................. Chapter 2 - Types, Operators and Expressions..................... 2.1 Variable Names................................. 2.2 Data Types and Sizes........................... 2.3 Constants...................................... 2.4 Declarations................................... 2.5 Arithmetic Operators........................... 2.6 Relational and Logical Operators............... 2.7 Type Conversions............................... 2.8 Increment and Decrement Operators.............. 2.9 Bitwise Operators.............................. 2.10 Assignment Operators and Expressions.......... 2.11 Conditional Expressions....................... 2.12 Precedence and Order of Evaluation............ Chapter 3 - Control Flow......................................... 3.1 Statements and Blocks.......................... 3.2 If-Else........................................ 3.3 Else-If........................................ 3.4 Switch......................................... 3.5 Loops - While and For.......................... 3.6 Loops - Do-While............................... 3.7 Break and Continue............................. 3.8 Goto and labels................................ Chapter 4 - Functions and Program Structure...................... 4.1 Basics of Functions............................ 4.2 Functions Returning Non-integers............... 4.3 External Variables............................. 4.4 Scope Rules.................................... 4.5 Header Files................................... 4.6 Static Variables................................ 4.7 Register Variables.............................. 4.8 Block Structure................................. 4.9 Initialization.................................. 4.10 Recursion...................................... 4.11 The C Preprocessor............................. 4.11.1 File Inclusion........................ 4.11.2 Macro Substitution.................... 4.11.3 Conditional Inclusion................. Chapter 5 - Pointers and Arrays.................................. 5.1 Pointers and Addresses......................... 5.2 Pointers and Function Arguments................ 5.3 Pointers and Arrays............................ 5.4 Address Arithmetic............................. 5.5 Character Pointers and Functions............... 5.6 Pointer Arrays; Pointers to Pointers........... 5.7 Multi-dimensional Arrays....................... 5.8 Initialization of Pointer Arrays............... 5.9 Pointers vs. Multi-dimensional Arrays.......... 5.10 Command-line Arguments........................ 5.11 Pointers to Functions......................... 5.12 Complicated Declarations...................... Chapter 6 - Structures........................................... 6.1 Basics of Structures........................... 6.2 Structures and Functions....................... 6.3 Arrays of Structures........................... 6.4 Pointers to Structures......................... 6.5 Self-referential Structures.................... 6.6 Table Lookup................................... 6.7 Typedef........................................ 6.8 Unions......................................... 6.9 Bit-fields..................................... Chapter 7 - Input and Output..................................... 7.1 Standard Input and Output....................... 7.2 Formatted Output - printf....................... 7.3 Variable-length Argument Lists.................. 7.4 Formatted Input - Scanf......................... 7.5 File Access..................................... 7.6 Error Handling - Stderr and Exit................ 7.7 Line Input and Output........................... 7.8 Miscellaneous Functions......................... 7.8.1 String Operations...................... 7.8.2 Character Class Testing and Conversion. 7.8.3 Ungetc................................. 7.8.4 Command Execution...................... 7.8.5 Storage Management..................... 7.8.6 Mathematical Functions................. 7.8.7 Random Number generation............... Chapter 8 - The UNIX System Interface............................ 8.1 File Descriptors............................... 8.2 Low Level I/O - Read and Write................. 8.3 Open, Creat, Close, Unlink..................... 8.4 Random Access - Lseek.......................... 8.5 Example - An implementation of Fopen and Getc.. 8.6 Example - Listing Directories.................. 8.7 Example - A Storage Allocator.................. Appendix A - Reference Manual.................................... A.1 Introduction................................... A.2 Lexical Conventions............................ A.2.1 Tokens................................ A.2.2 Comments.............................. A.2.3 Identifiers........................... A.2.4 Keywords.............................. A.2.5 Constants............................. A.2.6 String Literals....................... A.3 Syntax Notation................................ A.4 Meaning of Identifiers......................... A.4.1 Storage Class......................... A.4.2 Basic Types........................... A.4.3 Derived types......................... A.4.4 Type Qualifiers....................... A.5 Objects and Lvalues............................ A.6 Conversions.................................... A.6.1 Integral Promotion.................... A.6.2 Integral Conversions.................. A.6.3 Integer and Floating.................. A.6.4 Floating Types........................ A.6.5 Arithmetic Conversions................ A.6.6 Pointers and Integers................. A.6.7 Void.................................. A.6.8 Pointers to Void...................... A.7 Expressions.................................... A.7.1 Pointer Conversion.................... A.7.2 Primary Expressions................... A.7.3 Postfix Expressions................... A.7.4 Unary Operators....................... A.7.5 Casts................................. A.7.6 Multiplicative Operators.............. A.7.7 Additive Operators.................... A.7.8 Shift Operators....................... A.7.9 Relational Operators.................. A.7.10 Equality Operators................... A.7.11 Bitwise AND Operator................. A.7.12 Bitwise Exclusive OR Operator........ A.7.13 Bitwise Inclusive OR Operator........ A.7.14 Logical AND Operator................. A.7.15 Logical OR Operator.................. A.7.16 Conditional Operator................. A.7.17 Assignment Expressions............... A.7.18 Comma Operator.......................... A.7.19 Constant Expressions.................... A.8 Declarations..................................... A.8.1 Storage Class Specifiers................. A.8.2 Type Specifiers.......................... A.8.3 Structure and Union Declarations......... A.8.4 Enumerations............................. A.8.5 Declarators.............................. A.8.6 Meaning of Declarators................... A.8.7 Initialization........................... A.8.8 Type names............................... A.8.9 Typedef.................................. A.8.10 Type Equivalence........................ A.9 Statements....................................... A.9.1 Labeled Statements....................... A.9.2 Expression Statement..................... A.9.3 Compound Statement....................... A.9.4 Selection Statements..................... A.9.5 Iteration Statements..................... A.9.6 Jump statements.......................... A.10 External Declarations........................... A.10.1 Function Definitions.................... A.10.2 External Declarations................... A.11 Scope and Linkage............................... A.11.1 Lexical Scope........................... A.11.2 Linkage................................. A.12 Preprocessing................................... A.12.1 Trigraph Sequences...................... A.12.2 Line Splicing........................... A.12.3 Macro Definition and Expansion.......... A.12.4 File Inclusion.......................... A.12.5 Conditional Compilation................. A.12.6 Line Control............................ A.12.7 Error Generation........................ A.12.8 Pragmas................................. A.12.9 Null directive.......................... A.12.10 Predefined names....................... A.13 Grammar......................................... Appendix B - Standard Library.................................... B.1.1 File Operations................................ B.1.2 Formatted Output......................... B.1.3 Formatted Input.......................... B.1.4 Character Input and Output Functions..... B.1.5 Direct Input and Output Functions........ B.1.6 File Positioning Functions............... B.1.7 Error Functions.......................... B.2 Character Class Tests: ................. B.3 String Functions: ..................... B.4 Mathematical Functions: ................. B.5 Utility Functions: ....................

退格符 \b \b是退格符的意思，将光标回退一个字符的位置，可以结合空白字符使用达到类似删除的效果 1.回退符'\b'后面没有内容的情况原样输出 // 回退符\b后面，没有内容，则原样输出 System.out.println("x\b"); // x 回退符后面没有内容，则原样输出x System.out.println("xyzbbb\b\b"); // xyzbbb 回退符后面没有内容，则原样输出xyzbbb System.out.println("xyz\b\b\b"); /

\b退格符（回退符）回退符'\b'后面没有内容的情况，回退符'\b' 后面有内容的情况

c语言程序设计 1-10 编写一个将输入复制到输出的程序，并将其中的制表符替换为\t,把回退符替换为\b，把反斜杠替换为\ 这样就可以将制表符和回退符以可见的方式显示出来 #include <stdio.h> /* 编写一个将输入复制到输出的程序，并将其中的制表符替换为\t,把回退符替换为\b，把反斜杠替换为\\ 这样就可以将制表符和回退符以可见的方式显示出来 */ int mai...

在看KR的《C程序设计语言》时，做了一个看似很简单的练习，当键盘输入Backspace时输出回退符(\b)。试了下没成功，在网上搜索了下发现很多朋友都遇到了。所以简单的记录下，10年前就学C了，这个问题都没搞定，温故而知新，同时提醒自己基础很重要啊。使用的getchar(),不能捕获到键盘输入Backspace： #include #include int main() {

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