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 = ;
  long lengtharr[MAXWORDLEN + ];
  int wordlen = ;

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

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

　//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 == )
  {
    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 == '\t' || c == '\n' || c == EOF)
    {
      if(inspace == )
      {
        firstletter = ;
        inspace = ;

        if(wordlen <= MAXWORDLEN)
        {
          if(wordlen > )
          {
            thisval = ++lengtharr[wordlen - ];
            if(thisval > maxval)
            {
              maxval = thisval;
            }
          }
        }
        else
        {
          thisval = ++lengtharr[MAXWORDLEN];
          if(thisval > maxval)
          {
            maxval = thisval;
          }
        }
      }
      if(c == EOF)
      {
        done = ;
      }
    }
    else //统计当前单词的长度
    {
      if(inspace ==  || firstletter == )
      {
        wordlen = ;
        firstletter = ;
        inspace = ;
      }
      ++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 > ; thisval--)
  {
    printf("%4d  | ", thisval);
    for(thisidx = ; thisidx <= MAXWORDLEN; thisidx++)
    {
      if(lengtharr[thisidx] >= thisval)
      {
        printf("*  ");
      }
      else
      {
        printf("   ");
      }
    }
    printf("\n");
  }
  printf("      +");
  for(thisidx = ; thisidx <= MAXWORDLEN; thisidx++)
  {
    printf("---");
  }
  printf("\n       ");
  for(thisidx = ; thisidx < MAXWORDLEN; thisidx++)
  {
    printf("%2d ", thisidx + );
  }
  printf(">%d\n", MAXWORDLEN);

  return ;
}

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  | *  *  *
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  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  | *  *  *  *  *  *  *  *  *  *  *
      +---------------------------------
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