C将文件复制到结构中

Question

好的，所以我有一个带有整数的文件，例如：

14
22
82
53
61
74
47
95

我想将它复制到我的结构中，问题是我的结构有 2 列，我不知道如何将文件复制到一个中。

我的问题是：有没有像 qsort 这样快速简单的功能可以自动复制我的文件？

 #include <stdio.h>      /* printf */
 #include <stdlib.h>     /* qsort */

struct Element
{
int userId;
int score;
};

struct Element elements[] = { 
{1, 13},
{2,  9},
{3, 13},
{4, 19},
{5,  8},
{6, 11},
{7, 14},
{8, 17},
};

int ascendingSortCompareFunction (const void * a, const void * b)
{
   return (((struct Element *)a)->score - ((struct Element *)b)->score);
}

int descendingSortCompareFunction (const void * a, const void * b)
{
   return ((struct Element *)b)->score) - (((struct Element *)a)->score;
}

int main ()
{
int n;
int count;

count = sizeof(elements) / sizeof(elements[0]);

qsort(elements, count, sizeof(elements[0]), ascendingSortCompareFunction);
printf ("UserID\tScore (Ascending Sort)\n");
for (n = 0 ; n < count ; n++)
    printf ("%d\t%d\n", elements[n].userId, elements[n].score);

qsort(elements, count, sizeof(elements[0]), descendingSortCompareFunction);
printf ("UserID\tScore (Descending Sort)\n");
for (n = 0 ; n < count ; n++)
    printf ("%d\t%d\n", elements[n].userId, elements[n].score);

getchar();

return 0;
}

Answer 1

不确定是否有可用的功能，但手动完成不需要太多代码。

你打开文件：

FILE *fp;
fp = fopen("myfile.txt", "r")

然后循环读取文件，一次一行，将每个int插入到struct数组中：

//looping through file and array with i as a counter
fscanf(fp,"%d", &elements[i].score);

这假设您正在从文件中读取分数。希望这足以让您入门！

哦，然后关闭文件：

fclose(fp);

Answer 2

我几乎可以肯定这就是你要找的东西

#include <stdio.h>      /* printf */
#include <stdlib.h>     /* qsort */

struct Element
{
    int userId;
    int score;
};

int ascendingSortCompareFunction (const void * a, const void * b)
{
   return (((struct Element *)a)->score - ((struct Element *)b)->score);
}

int descendingSortCompareFunction (const void * a, const void * b)
{
   return -ascendingSortCompareFunction(a, b);
}

void readFromFile(const char *const filename,  struct Element **elements, size_t *count)
{
    FILE *file;
    void *auxiliary;
    int   index;
    int   score;
    char  line[128];

    if ((elements == NULL) || (count == NULL))
        return;
    *count    = 0;
    *elements = NULL;
    file      = fopen(filename, "r");
    if (file == NULL)
        return;

    index = 0;
    while (fgets(line, sizeof(line), file) != NULL)
    {
        if (sscanf(line, "%d", &score) == 1)
        {
            auxiliary = realloc(*elements, (1 + *count) * sizeof(struct Element));
            if (auxiliary == NULL)
            {
                free(*elements);
                fclose(file);

                *elements = NULL;

                return;
            }
            *elements                  = auxiliary;
            (*elements)[*count].userId = 1 + index;
            (*elements)[*count].score  = score;

            *count += 1;
            index  += 1;
        }
    }
    fclose(file);
}

int main ()
{
    size_t          count;
    size_t          n;
    struct Element *elements;
    size_t          size;

    elements = NULL;
    size     = sizeof(struct Element);
    count    = 0;

    readFromFile("/home/iharob/file.txt", &elements, &count);
    if ((elements != NULL) && (count > 0))
    {
        qsort(elements, count, size, ascendingSortCompareFunction);
        printf ("UserID\tScore (Ascending Sort)\n");

        for (n = 0 ; n < count ; n++)
            printf ("%d\t%d\n", elements[n].userId, elements[n].score);

        qsort(elements, count, size, descendingSortCompareFunction);
        printf ("UserID\tScore (Descending Sort)\n");

        for (n = 0 ; n < count ; n++)
            printf ("%d\t%d\n", elements[n].userId, elements[n].score);

        free(elements);
    }
    getchar();

    return 0;
}