C - 将字符串(句子)转换为字符串列表

Question

我需要将一个句子(例如“Hello world”)复制到一个字符串列表中，意思是复制到一个字符数组中，其中每 2 个单词由 '\0' 分隔。请注意，单词被定义为一行中没有空格的任意数量的字符。

因此，每当我的程序在一行中检测到任意数量的空格(包括仅 1 个空格)时，它应该使用单个 '\0' 代替。

问题是，在我的 target 字符数组中第一次写入 '\0' 后，我无法再写入它了。我猜是因为 '\0' 表示字符串结尾，但在我的例子中，我试图在 char 数组中实现一个字符串列表，所以我必须有 '\0'每2个字之间。

基本上我的问题是如何在放置 '\0' 后继续写入 char 数组？

到目前为止，这是我的代码(如您所见，我还在每次迭代时检查 traget 中是否有足够的空间，但那部分工作正常，所以并​​不是很有趣)

int strListFromWords(const char* source, char* target, int buffSize)
{
    if (buffSize < 2) return -1;
    char* sCurrentPointer = source;
    char* tCurrentPointer = target;
    int charsInTarget = 0;
    while (*sCurrentPointer != '\0')            // While not end of string
    {
        if (charsInTarget + 2 < buffSize)   // if there is enough space in target for current char 
        {
            charsInTarget++;
            if (!isspace(*sCurrentPointer))         // if current char isn't space
            {
                *tCurrentPointer = *sCurrentPointer;
                sCurrentPointer++;
                tCurrentPointer++;
            }
            else
            {
                *tCurrentPointer = '\0';            // PROBLEMATIC LINE put '\0' instead of spcace (in target)

                sCurrentPointer++;                  // goto next char in source
                tCurrentPointer++;                  // goto next position in target
                while (isspace(*sCurrentPointer))   // while there are more spaces in a row
                {
                    sCurrentPointer++;              // just skip them without messing with target
                }
            }
        }
        else
            {                                   // Not enough space
                emptyStrList(target);
                return 0;
            }
        }
    *tCurrentPointer = '\0';
    *(tCurrentPointer + 1) = '\0';
    return numStrsInList(target);
    }

谢谢，

Answer 1

没有什么可以阻止你写过去的 0。

我使用以下代码段测试了您的函数，它正确返回了 word_count。目标缓冲区将包含以 0 结尾的单词，并在末尾加上一个额外的 0。我想，这就是意图。

#include <conio.h> // for getch()
#include <malloc.h>
#include <string.h>

int main()
{
   char* source = " Hello World!\nThis is line number two.\n\n \n  \n This is the last line";

   size_t buflen = strlen(source);
   char* target = (char*)malloc(strlen(source));

   int word_count = strListFromWords(source, target, buflen);
   printTarget(target);

   free(target);
   getch();
}

此函数将显示整个目标缓冲区:

void printTarget(const char* target) {
       char prev = ' ';
       for (int i = 0;; i++) {
          if (target[i])
             putch(target[i]);
          else {
             putch('\n');
             if (!prev)
                break;
          }
          prev = target[i];
       }
    }

为了编译，需要做一些小改动:

#include <stdio.h>
#include <ctype.h>

int strListFromWords(const char* source, char* target, int buffSize)
{
   if (buffSize < 2) return -1;
   char* sCurrentPointer = (char*)source;
   char* tCurrentPointer = target;
   int charsInTarget = 0;
   int numStrsInList = 0;

   while (*sCurrentPointer != '\0')            // While not end of string
   {
      if (charsInTarget + 2 < buffSize)   // if there is enough space in target for current char 
      {
         charsInTarget++;
         if (!isspace(*sCurrentPointer))         // if current char isn't space
         {
            *tCurrentPointer = *sCurrentPointer;
            sCurrentPointer++;
            tCurrentPointer++;
         }
         else
         {
            *tCurrentPointer = '\0';            // PROBLEMATIC LINE put '\0' instead of spcace (in target)
            numStrsInList++;

            sCurrentPointer++;                  // goto next char in source
            tCurrentPointer++;                  // goto next position in target
            while (isspace(*sCurrentPointer))   // while there are more spaces in a row
            {
               sCurrentPointer++;              // just skip them without messing with target
            }
         }
      }
      else
      {                                   // Not enough space
         //emptyStrList(target);
         return 0;
      }
   }

   *tCurrentPointer = 0;
   *(tCurrentPointer + 1) = 0;
   return numStrsInList;
}

请注意，我只回答了被问到的问题。