在文件中计数的单词，如 C 中的 linux wc 命令 [英] words counting in file like linux wc command in C

问题描述

我正在尝试编写一些类似于 Linux 命令 wc 的东西来计算任何类型文件中的字数、换行符和字节数，并且我只能使用 C 函数读取.我已经编写了这段代码，我得到了正确的换行符和字节值，但我没有得到正确的计数字值.

I am trying to write something that works like the Linux command wc to count words, new lines and bytes in any kind of files and i can only use the C function read. I have written this code and i am getting the correct values for newlines and bytes but i am not getting the correct value for counted words.

int bytes = 0;
int words = 0;
int newLine = 0;
char buffer[1];
int file = open(myfile,O_RDONLY);
if(file == -1){
  printf("can not find :%s
",myfile);
}
else{
  char last = 'c'; 
  while(read(file,buffer,1)==1){
    bytes++;
    if(buffer[0]==' ' && last!=' ' && last!='
'){
      words++;
    }
    else if(buffer[0]=='
'){
      newLine++;
      if(last!=' ' && last!='
'){
        words++;
      }
    }
    last = buffer[0];
  }        
  printf("%d %d %d %s
",newLine,words,bytes,myfile);        
} 

推荐答案

你应该颠倒你的逻辑.与其寻找空格并增加字数，不如寻找非空格来增加字数.此外，它可以帮助使用状态变量而不是查看最后一个字符:

You should reverse your logic. Rather than look for a space, and increment your word count, look for a non-space to increment the word count. Also, it can help to use a state variable versus looking at the last char:

int main(void)
{
   const char *myfile = "test.txt";
   int bytes = 0;
   int words = 0;
   int newLine = 0;
   char buffer[1];
   int file = open(myfile,O_RDONLY);
   enum states { WHITESPACE, WORD };
   int state = WHITESPACE;
   if(file == -1){
      printf("can not find :%s
",myfile);
   }
   else{
      char last = ' '; 
      while (read(file,buffer,1) ==1 )
      {
         bytes++;
         if ( buffer[0]== ' ' || buffer[0] == '	'  )
         {
            state = WHITESPACE;
         }
         else if (buffer[0]=='
')
         {
            newLine++;
            state = WHITESPACE;
         }
         else 
         {
            if ( state == WHITESPACE )
            {
               words++;
            }
            state = WORD;
         }
         last = buffer[0];
      }        
      printf("%d %d %d %s
",newLine,words,bytes,myfile);        
   } 

}

似乎 wc 有一些关于标点符号不是单词的逻辑，这段代码无法处理.

It appears that wc has some logic with respect to punctuation characters not being words, that this code does not handle.

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