这怎么了整天都无法解决... [英] What's wrong with this? Cannot figure it out for a WHOLE DAY...

问题描述

我是C语言的新手，目前正在阅读K& R的C编程语言.

今天，我尝试从本书中解决2个简单的练习，但发现我的代码有问题-但我不知道为什么.有人可以帮我吗? THX很多！

PS，我正在使用Microsoft的visual studio 2010进行编码.

问题1:编写程序以将其输入复制到其输出，用一个空格替换一个或多个空格的每个字符串.

我的代码:

I am a totally newcomer to C and I am currently reading K&R''s The C Programming Language.

Today I try to solve 2 simple exercises from this book and I found something wrong with my code----but I don''t know why. Could anybody help me about them? THX alot!

PS, I am using Microsoft''s visual studio 2010 to code.

Q1: write a program to copy its input to its output, replacing each string of one or more blanks by a single blank.

my code:

#include <stdio.h>
#include <stdlib.h>
#define OUT 0
#define IN 1
main()
{
    int c, state;

    state=IN;

    printf("This is a minyfunction designed to omit blanks you typed in into one blank\n");
    printf("Please type in 'Control + Z ' in a new line when you have finished typing\n");


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

        if ((c=getchar())!=' ')
        {
            if (state==OUT)
            {
                printf(" ");
                state=IN;
                putchar(c);
            }
            else putchar(c);
        }
        else state=OUT;
    }
    system("Pause");

}

可以将几个空格换成一个空格，但是我输入的每两个字符都会被省略，而且我也不知道为什么...


Q2:编写程序以将其输入复制到其输出，用\ t替换每个制表符，用\ b替换每个退格键，并用\\替换每个反斜杠.

我的代码:

The exchange from several blanks into one blank works out okay, but for every two characters I type in, one of them will be omitted and I don''t know why...


Q2: Write a program to copy its input to its output, replacing each tab by \t, each backspace by \b, and each backslash by \\.

my code:

#include <stdio.h>

main()
{
    int c;

    while ((c=getchar()!=EOF))
    {
        if (c==' ')
        {
            printf("\\n");
        }
        else if (c=='\t')
        {
            printf("\\t");
        }
        else if (c=='\n')
        {
            printf("\\n");
        }
        else if (c=='\\')
        {
            printf("\\");
        }
        else
        putchar(c);
    }

    system("Pause");
}

问题是屏幕上的输出字符全部变成笑脸的迹象...我不知道为什么这些字符变成了模仿的面孔，我希望有人能帮助我修改这些代码以使其正常工作.

对不起我的英语真的很差----我不是一个母语的人...

THX为您提供帮助！

The problem is that the output characters on screen all turn to be signs of smiling faces...I don''t know why these characters become similing faces and I hope anybody could help me to revise these code to make it work out okay.

Sorry about my really poor English----I am not a native speaker...

THX for your help!

推荐答案

我已经为您完成了作业:

Ive done your homework for you:

void main()
{
  struct
  {
    static int space(TCHAR c){ return (' '==c)||('\t'==c)||('\r'==c)||('\n'==c); }
    static int escape(TCHAR c){ return ('\t'==c)||('\b'==c)||('\\'==c); }
  }      is;
  TCHAR  c;
  int    s = 0;
  // Q1: solution
  while('\x1a'/*ctrl+z*/!=(c=_gettch()))
  {
    if(is.space(c))
    {
      if(0==s++) _puttchar(' ');
    }
    else
    {
      _puttchar(c);
      s = 0;
    }
  }
  // Q2: solution
  while('\x1a'/*ctrl+z*/!=(c=_gettch()))
  {
    if(is.escape(c))
    {
      _puttchar('\\');
      _puttchar('\\');
    }
    else
    {
      _puttchar(c);
    }
  }
}

问候.

Regards.

第一个问题:

在此循环中，您将通过检查EOF来删除所有其他字符，并在其后添加一条同时调用getchar()的if语句，您每次循环迭代仅应调用一次getchar():

First Question:

In this loop, you''re removing every other character by checking for EOF and following that up with an if statement that calls getchar() as well, you should only call getchar() once per loop iteration:

while ((c=getchar())!=EOF)
{
    if ((c=getchar())!=' ')
    {
      ...
    }
    else ...;
}

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