c - 在C中的字符串中为每个单词的结尾添加空格

Question

这里我有一个字符串:

*line = "123 567 890  ";

末尾有两个空格。我希望将这 2 个空格添加到 3 的末尾和 7 的末尾，使其像这样:

"123  567  890"

我试图实现以下步骤:

1. 通过单词列表(字符串数组)将字符串解析为单词。从上游函数中，我将获得变量 word_count、*line 和 remain 的值。
2. 在最后用一个空格将它们连接起来。
3. 按从左到右的优先顺序分配空间。
4. 将所有内容连接在一起，使其成为一个新的*行。

Word_count 是*行中的单词数，remain 是剩余的空格数。

这是我的错误代码的一部分:

int add_space(char *line, int remain, int word_count)
{
    if (remain == 0.0)
        return 0; // Don't need to operate.

    int ret;
    char arr[word_count][line_width];
    memset(arr, 0, word_count * line_width * sizeof(char));

    char *blank = calloc(line_width, sizeof(char));
    if (blank == NULL)
    {
        fprintf(stderr, "calloc for arr error!\n");
        return -1;
    }

    for (int i = 0; i < word_count; i++)
    {
        ret = sscanf(line, "%s", arr[i]); // gdb shows somehow it won't read in.
        if (ret != 1)
        {
            fprintf(stderr, "Error occured!\n");
            return -1;
        }
        arr[i] = strcat(arr[i], " "); // won't compile.
    }

    size_t spaces = remain / (word_count * 1.0);
    memset(blank, ' ', spaces + 1);
    for (int i = 0; i < word_count - 1; i++)
    {
        arr[0] = strcat(arr[i], blank); // won't compile.
    }

    memset(blank, ' ', spaces);
    arr[word_count-1] = strcat(arr[word_count-1], blank);

    for (int i = 1; i < word_count; i++)
    {
        arr[0] = strcat(arr[0], arr[i]);
    }

    free(blank);
    return 0;
}

它不工作了，你能帮我找到不工作的部分并修复它们吗？谢谢你们。

Answer 1

这是一个替代建议 - 可能更快，并且使用更少的内存。

首先 - 注意您返回的行将与您开始的行大小相同 - 所以我们只需要移动单词并添加空格。据我所知，您当前的代码似乎没有尝试实际返回固定字符串……

从字符串末尾开始计算“额外空格”的数量(我认为这是您的remain 值)。现在向后遍历字符串，直到找到最后一个单词的开头，然后移动它。

我写了一个示例 - 使用一些调试语句使发生的事情更加明显，并在添加空格时包含“”而不是“”。这会更清楚地向您展示它在做什么(尽管您在使用此代码时显然希望将“”替换为“”)。

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

int distributeSpaces(char* s, int wordCount, int spaceCount);

int main(void) {
  char *myString = "There is a house in New Orleans       ";
  char *sCopy;
  sCopy = malloc(strlen(myString)+1);
  strcpy(sCopy, myString);
  printf("Initial string: '%s'\n", myString);
  distributeSpaces(sCopy, 7, 7);
  printf("\nString is now '%s'\n", sCopy);
  return 0;
}

int distributeSpaces(char* s, int wordCount, int spaceCount) {
  int ii, length;
  int wordLength, wordEnd;
  int spaceLeft = spaceCount + 1;
  length = strlen(s);
  printf("string is %d characters long\n", length);
  wordEnd = length - spaceLeft - 1;
  wordLength = 0;
  for(ii = length - spaceLeft - 1; ii > 0; ii--) {
    wordLength++;
    if(s[ii] == ' ') {
      // printf("found space - moving %d characters from %d to %d\n", wordLength, ii, ii+spaceLeft);
      printf("before memmove, string is '%s'\n", s);
      memmove(&s[ii+spaceLeft], &s[ii+1], wordLength);
      printf("after memmove, string is now '%s'\n", s);
      memset(&s[ii], '*', spaceLeft);
      printf("after memset, string is now '%s'\n", s);
      spaceLeft -= spaceLeft / wordCount--;
      // printf("space left is now %d\n", spaceLeft);
      wordLength = 0;
      ii--;
    }
  }
  return 0;
}

输出:

Initial string: 'There is a house in New Orleans       '
string is 38 characters long
before memmove, string is 'There is a house in New Orleans       '
after memmove, string is now 'There is a house in New OrleansOrleans'
after memset, string is now 'There is a house in New********Orleans'
before memmove, string is 'There is a house in New********Orleans'
after memmove, string is now 'There is a house in New***New**Orleans'
after memset, string is now 'There is a house in*******New**Orleans'
before memmove, string is 'There is a house in*******New**Orleans'
after memmove, string is now 'There is a house in***in**New**Orleans'
after memset, string is now 'There is a house******in**New**Orleans'
before memmove, string is 'There is a house******in**New**Orleans'
after memmove, string is now 'There is a houshouse**in**New**Orleans'
after memset, string is now 'There is a*****house**in**New**Orleans'
before memmove, string is 'There is a*****house**in**New**Orleans'
after memmove, string is now 'There is a**a**house**in**New**Orleans'
after memset, string is now 'There is****a**house**in**New**Orleans'
before memmove, string is 'There is****a**house**in**New**Orleans'
after memmove, string is now 'There isis**a**house**in**New**Orleans'
after memset, string is now 'There***is**a**house**in**New**Orleans'

String is now 'There***is**a**house**in**New**Orleans'

我认为这就是您所追求的。