Question

我正在读取文件中的单词列表并尝试逐行排序。我可以阅读每一行并打印好的单词，但我似乎无法单独排序每一行。第一行是排序的，但第二行不是。谁能看到我哪里出错了？谢谢！

    int fd;
    int n_char = 0;
    int charCount = 0, wordCount = 0, lineCount = 0;
    int wordsPerLine[100];

    char buffer;
    char words[6][9];

    fd = open(inputfile, O_RDONLY);
    if (fd == -1) {
        exit(1);
    }

    wordsPerLine[0] = 0;

    /* use the read system call to obtain 10 characters from fd */
    while( (n_char = read(fd, &buffer, sizeof(char))) != 0) {

        if (buffer == '\n' || buffer == ' ') {
            words[wordCount][charCount] = '\0';
            charCount = 0;
            wordCount++;
            wordsPerLine[lineCount] += 1;
            if (buffer == '\n') {
                lineCount++;
                wordsPerLine[lineCount] = 0;
            }
        } else {
            words[wordCount][charCount++] = buffer;
        }
    }

    printf("Num Words: %d  ---  Num Lines: %d\n", wordCount, lineCount);

    char tmp[9];

    int m, n;
    int i, x, totalCount = 0;
    for (i = 0; i < lineCount; i++) {
        for (x = 0; x < wordsPerLine[i]; x++) {

            /* iterate through each word 'm' in line 'i' */
            for(m = 0; m < wordsPerLine[i]; m++) {
                for(n = 0; n < wordsPerLine[i]; n++) {
                    if(strcmp(words[n-1], words[n])>0) {
                        strcpy(tmp, words[n-1]);
                        strcpy(words[n-1], words[n]);
                        strcpy(words[n], tmp);
                    }
                }
            } /* end sorting */

        }
    }

    printf("Sorted:\n");
    totalCount = 0;
    for(i = 0; i < lineCount; i++) {
        printf("Line %d (%d words)\n", i + 1, wordsPerLine[i]);
        for(x = 0; x < wordsPerLine[i]; x++) {
            printf("%s\n", words[totalCount++]);
        }
    }

我的示例输入文件是：

great day out
foo bar food

Answer 1

让我们去一小部分......

要查看问题是否在阅读中，请评论阅读部分并尝试添加：

 char words[][9] = {"great", "day", "out", "foo", "bar", "food"};

并将计数器设置为使用此输入的值...

你的循环是从界限中访问一些数据......我建议你首先尝试使用一组数字排序代码，看看它是否正确排序......

#include<stdio.h>
#define N 6
int main()
{
   char words[][9] = {"great", "day", "out", "foo", "bar", "food"};
   int numbers[] = {20, 10, 50, 5, 30, -50};
   int i, j, temp;

   for(i = 0; i < N - 1; i++)
      for(j = 0; j < N - 1; j++)
          if(numbers[j] > numbers[j + 1])
          {
             temp = numbers[j];
             numbers[j] = numbers[j + 1];
             numbers[j + 1] = temp;
          }


    for(i = 0; i < N; i++)
    {
        printf("%d\n", numbers[i]);
        //printf("%s\n", words[i]);
    }
}

另请注意，这是冒泡排序效率最低的（但与您提供的相同），您可以通过添加变量来检查内部循环中的某些更改（例如，这意味着它是已经排序，你可以停止排序）...

此外，在outter循环上的每次迭代之后，一个元素将被放置在其最终位置（尝试找出哪一个），这意味着您不需要在下一次迭代中考虑此元素，所以在外循环中的每次迭代之后，内循环中比较的元素数量可以减少1 ...

您可以找到有关冒泡排序here

的更多信息

Answer 2

/* iterate through each line */
for (i = 0; i < lineCount; i++) { 

    /* iterate through each word 'm' in line 'i' */
    for(m = 0; m < wordsPerLine[i]; m++) {
        for(n = m+1; n < wordsPerLine[i]; n++) {
            if(strcmp(words[n + totalCount], words[m + totalCount]) < 0) {
                strcpy(tmp, words[m + totalCount]);
                strcpy(words[m + totalCount], words[n + totalCount]);
                strcpy(words[n + totalCount], tmp);
            }
        }
    } /* end sorting */  
    totalCount += wordsPerLine[i];
}

我只需要保持每行每个单词的运行计数，所以我知道要开始与

比较的行

在C中对字符串的2D数组进行排序

2 个答案: