Question

编辑：修复了代码中的重复错误。我试图创建一个从标准输入读入的单词频率分析程序。我有两个问题。

目前我正在使用＆＃39; \ n＆＃39;为了表明我的程序何时应该停止读取输入，我需要它阅读，直到用户完成输入。使用EOF或空终止符＆＃39; \ 0＆＃39;
这可能是一个愚蠢的问题，但我无法弄清楚我的输出有什么问题，它每次都会使字母翻倍。

示例输入：＆＃34;这是对频率的测试程序，对于＆＃34;

输出：

thhiiss 1
iiss 2
aa 2
tteesstt 2
ooff 1
tthhee 1
pprrooggrraamm 1
ffoorr 3
ffrreeqquueennccyy 1
tthhiiss 1

正如你可以看到每个单词的计数接近正确，但无法弄清楚为什么这些字母是重复的。这是我使用的代码：

#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include "list.h"

#define MAXWORD 100

//===========================================================================
struct lnode {
    struct lnode *next;
    struct lnode *counter;
    struct lnode *pLast;   
    struct lnode *prev;
    struct lnode *head;
    char *word;
    int line;
    int count;
    int freq;
};

struct lnode *start = NULL;

//===========================================================================
struct lnode *createWordCounter(char *str)
  {
     struct lnode *pCounter = NULL;
     pCounter = (struct lnode*)malloc(sizeof(struct lnode));
     pCounter->word = (char*)malloc(strlen(str)+1);
     strcpy(pCounter->word, str);
     pCounter->freq = 1;
     pCounter->next = NULL;
     return pCounter;
  }
//===========================================================================
void addWord(char *str)
{
  struct lnode *pCounter = NULL;
  struct lnode *pLast = NULL;

  if(start == NULL)
  {
    start = createWordCounter(str);
    return;
  }
  // If the word is in the list, increment its count 
  pCounter = start;
  int temp = pCounter->freq;
  while(pCounter != NULL)
  {
    if(strcmp(str, pCounter->word) == 0)
    {
      pCounter->freq++;
      return;
    }
    pLast = pCounter;            
    pCounter = pCounter->next;  
  }

  // Word is not in the list, add it 
  pLast->next = createWordCounter(str);
}
//===========================================================================
int getNextWord(char *buf, int bufsize) {
    char *p = buf;
    char ch;
    do {
        ch = getchar();
        if (ch == '\n') 
            return 0;
        } while (!((ch >= 'A' && ch <= 'Z')||( ch >= 'a' && ch <= 'z')));
    do {
        if (p - buf < bufsize - 1){
             if( ch >= 97 && ch <= 122)//making the ch lowercase if needed
                   *p++ = ch;
             else{ch += 32;
                  *p++ = ch;}
              }//End of if
        ch = getchar();
        } while (((ch >= 'A' && ch <= 'Z')||( ch >= 'a' && ch <= 'z')));
        *p = '\0';
        return 1;
        }
//===========================================================================
void show(struct lnode *pWord)
{
printf("%s %i\n", pWord->word, pWord->freq);
}
//===========================================================================

int main(){
    struct lnode *counter = NULL;
    int size = 1000;
    char buf[MAXWORD];
    while(getNextWord(buf, size) != 0 ){
        addWord(buf);
    }

    counter = start;

    while(counter != NULL)
    {
        show(counter);
        counter = counter->next;
    }

    counter = start;

    while(counter != NULL)
    {
    free(counter->word);
    start = counter;
    counter = counter->next;
    free(start);
    }

return 0;
}

这是我第一次发帖，所以如果我做错了请告诉我。任何帮助表示赞赏。

感谢。

Answer 1

请仔细查看，将ch两次分配给*p

     if( ch >= 97 && ch <= 122)//making the ch lowercase if needed
           *p++ = ch;
     else{ch += 32;}
       *p++ = ch;

我认为else语句中的尾部“}”是错误的。

     if( ch >= 97 && ch <= 122) { //making the ch lowercase if needed
           *p++ = ch;
     } else {
       ch += 32;
       *p++ = ch;
     }

此外，如果您了解这些功能，您的代码将更具可读性 isalpha，islower，isupper，tolower，toupper。信息 man ctype 。

Answer 2

Would it be better to use EOF or the null terminator '\0' ?

使用EOF，因为如果按ctl+D getchar()，请将输入视为EOF。您还可以使用\n或使用带有\n，EOF

的OR逻辑

what is wrong with my output it doubles the letters up every time ?

请参阅以下功能getNextWord()

中的代码

   if( ch >= 97 && ch <= 122)//making the ch lowercase if needed
           *p++ = ch;   
      //this checks if input character is lowercase character, then store it into buffer
     else{ch += 32;} // if input character is lowercase character, won't execute else part
          *p++ = ch;   
          // now again you are copying same input character into buffer next location

修改上述部分。

C：链接列表字频率 - 标准输入

2 个答案: