c程序设计语言_习题1-13_统计输入中单词的长度，并且根据不同长度出现的次数绘制相应的直方图

Write a program to print a histogram of the lengths of words in its input. It is easy to draw the histogram with the bars horizontal; a vertical orientation is more challenging.
统计输入中单词的长度，并且绘制相应的直方图。水平的直方图比较容易绘制，垂直的直方图较困难一些。

/* This program was the subject of a thread in comp.lang.c, because of the way it handled EOF.
 * The complaint was that, in the event of a text file's last line not ending with a newline,
 * this program would not count the last word. I objected somewhat to this complaint, on the
 * grounds that "if it hasn't got a newline at the end of each line, it isn't a text file".
 *
 * These grounds turned out to be incorrect. Whether such a file is a text file turns out to
 * be implementation-defined. I'd had a go at checking my facts, and had - as it turns out -
 * checked the wrong facts! (sigh)
 *
 * It cost me an extra variable. It turned out that the least disturbing way to modify the
 * program (I always look for the least disturbing way) was to replace the traditional
 * while((c = getchar()) != EOF) with an EOF test actually inside the loop body. This meant
 * adding an extra variable, but is undoubtedly worth the cost, because it means the program
 * can now handle other people's text files as well as my own. As Ben Pfaff said at the
 * time, "Be liberal in what you accept, strict in what you produce". Sound advice.
 *
 * The new version has, of course, been tested, and does now accept text files not ending in
 * newlines.
 *
 * I have, of course, regenerated the sample output from this program. Actually, there's no
 * "of course" about it - I nearly forgot.
 */

#include <stdio.h>

#define MAXWORDLEN 10

int main(void)
{
  int c;
  int inspace = 0;
  long lengtharr[MAXWORDLEN + 1];
  int wordlen = 0;

  int firstletter = 1;
  long thisval = 0;  //这个变量对于绘制垂直直方图，很有作用。
  long maxval = 0;
  int thisidx = 0;
  int done = 0;


  for(thisidx = 0; thisidx <= MAXWORDLEN; thisidx++)
  {
    lengtharr[thisidx] = 0;
  }


　//为什么不利用 while((c = getchar()) != EOF) 进行接收判断一起进行？这可以处理那些不是以新行结尾的文件。
  while(done == 0)
  {
    c = getchar();

　　//空格、换行、制表、EOF代表单词的结束，可以根据上一个单词的wordlen做统计了，并存放到lengtharr[wordlen - 1]  
    if(c == ' ' || c == '	' || c == '
' || c == EOF)
    {
      if(inspace == 0)
      {
        firstletter = 0;
        inspace = 1;

        if(wordlen <= MAXWORDLEN)
        {
          if(wordlen > 0)
          {
            thisval = ++lengtharr[wordlen - 1];
            if(thisval > maxval)
            {
              maxval = thisval;
            }
          }
        }
        else
        {
          thisval = ++lengtharr[MAXWORDLEN];
          if(thisval > maxval)
          {
            maxval = thisval;
          }
        }
      }
      if(c == EOF)
      {
        done = 1;
      }
    }
    else //统计当前单词的长度
    {
      if(inspace == 1 || firstletter == 1)
      {
        wordlen = 0;
        firstletter = 0;
        inspace = 0;
      }
      ++wordlen;
    }
  }

 //绘制垂直直方图，这个算法是可以借鉴的。不利用数组存储，而是根据指标变量thisval，也就是当前最大的直方图峰值来绘图。
  for(thisval = maxval; thisval > 0; thisval--)
  {
    printf("%4d  | ", thisval);
    for(thisidx = 0; thisidx <= MAXWORDLEN; thisidx++)
    {
      if(lengtharr[thisidx] >= thisval)
      {
        printf("*  ");
      }
      else
      {
        printf("   ");
      }
    }
    printf("
");
  }

  printf("      +");
  for(thisidx = 0; thisidx <= MAXWORDLEN; thisidx++)
  {
    printf("---");
  }
  printf("
       ");
  for(thisidx = 0; thisidx < MAXWORDLEN; thisidx++)
  {
    printf("%2d ", thisidx + 1);
  }
  printf(">%d
", MAXWORDLEN);

  return 0;
}

样本输出

Here's the output of the program when given its own source as input:

 113  | *                                
 112  | *                                
 111  | *                                
 110  | *                                
 109  | *                                
 108  | *                                
 107  | *                                
 106  | *                                
 105  | *                                
 104  | *                                
 103  | *                                
 102  | *                                
 101  | *                                
 100  | *                                
  99  | *                                
  98  | *                                
  97  | *                                
  96  | *                                
  95  | *                                
  94  | *  *                             
  93  | *  *                             
  92  | *  *                             
  91  | *  *                             
  90  | *  *                             
  89  | *  *                             
  88  | *  *                             
  87  | *  *                             
  86  | *  *                             
  85  | *  *                             
  84  | *  *                             
  83  | *  *                             
  82  | *  *                             
  81  | *  *                             
  80  | *  *                             
  79  | *  *                             
  78  | *  *                             
  77  | *  *                             
  76  | *  *                             
  75  | *  *                             
  74  | *  *                             
  73  | *  *                             
  72  | *  *                             
  71  | *  *                             
  70  | *  *                             
  69  | *  *                             
  68  | *  *                             
  67  | *  *                             
  66  | *  *                             
  65  | *  *                             
  64  | *  *                             
  63  | *  *  *                          
  62  | *  *  *                          
  61  | *  *  *                          
  60  | *  *  *                          
  59  | *  *  *                          
  58  | *  *  *                          
  57  | *  *  *                          
  56  | *  *  *                          
  55  | *  *  *                          
  54  | *  *  *                          
  53  | *  *  *                          
  52  | *  *  *  *                       
  51  | *  *  *  *                       
  50  | *  *  *  *                       
  49  | *  *  *  *                       
  48  | *  *  *  *                       
  47  | *  *  *  *                       
  46  | *  *  *  *                       
  45  | *  *  *  *                       
  44  | *  *  *  *                       
  43  | *  *  *  *        *              
  42  | *  *  *  *        *              
  41  | *  *  *  *        *              
  40  | *  *  *  *        *              
  39  | *  *  *  *        *              
  38  | *  *  *  *        *              
  37  | *  *  *  *        *              
  36  | *  *  *  *        *              
  35  | *  *  *  *        *              
  34  | *  *  *  *        *              
  33  | *  *  *  *        *              
  32  | *  *  *  *        *              
  31  | *  *  *  *        *              
  30  | *  *  *  *        *           *  
  29  | *  *  *  *        *           *  
  28  | *  *  *  *  *     *           *  
  27  | *  *  *  *  *     *           *  
  26  | *  *  *  *  *     *           *  
  25  | *  *  *  *  *  *  *           *  
  24  | *  *  *  *  *  *  *           *  
  23  | *  *  *  *  *  *  *           *  
  22  | *  *  *  *  *  *  *        *  *  
  21  | *  *  *  *  *  *  *        *  *  
  20  | *  *  *  *  *  *  *        *  *  
  19  | *  *  *  *  *  *  *        *  *  
  18  | *  *  *  *  *  *  *        *  *  
  17  | *  *  *  *  *  *  *        *  *  
  16  | *  *  *  *  *  *  *        *  *  
  15  | *  *  *  *  *  *  *        *  *  
  14  | *  *  *  *  *  *  *  *     *  *  
  13  | *  *  *  *  *  *  *  *     *  *  
  12  | *  *  *  *  *  *  *  *     *  *  
  11  | *  *  *  *  *  *  *  *     *  *  
  10  | *  *  *  *  *  *  *  *     *  *  
   9  | *  *  *  *  *  *  *  *  *  *  *  
   8  | *  *  *  *  *  *  *  *  *  *  *  
   7  | *  *  *  *  *  *  *  *  *  *  *  
   6  | *  *  *  *  *  *  *  *  *  *  *  
   5  | *  *  *  *  *  *  *  *  *  *  *  
   4  | *  *  *  *  *  *  *  *  *  *  *  
   3  | *  *  *  *  *  *  *  *  *  *  *  
   2  | *  *  *  *  *  *  *  *  *  *  *  
   1  | *  *  *  *  *  *  *  *  *  *  *  
      +---------------------------------
        1  2  3  4  5  6  7  8  9 10 >10