Question

我必须构建一个从文件中读取Template.register.events({ 'click .register': function(e) { e.preventDefault(); var getUser = $("#username").val(); var getEmail = $("#email").val(); var getPassword = $("#password").val(); } });和backer信息（结构）的函数。如果文件不存在，请通知用户，创建新文件并显示主菜单。文件打开后，通过为从文件读取的每个条目动态分配足够的内存，将数据读入结构数组。这是我走了多远。我不确定如何处理结构数组或正确分配内存。这是一个我不那么强大的话题。

reward

Answer 1

用于将文件加载到struct backer的数组中，其格式为：

int i;
FILE *backers;
struct backer *backer_array = NULL;
size_t backer_size = 0;
size_t bytes_read;

if ((backers = fopen("backers.txt", "rb")) == NULL) {
    printf("File not found \n New  backers file created \n");
}
else{
    /* Get the file size. */
    fseek(backers, 0 , SEEK_END);
    backer_size = ftell(backers);
    rewind(backers);

    /* Make sure that file size is an integral number of records. */
    backer_size = backer_size - (backer_size % sizeof(struct backer));

    /* Allocate space. */
    if (backer_size > 0) {
        backer_array = malloc(backer_size);
    }

    /* Read the entire file in one read. */
    if (backer_array) {
        bytes_read = fread (backer_array, 1, backer_size, backers);
        /* backer_size will now represent the number of elements in the array. */
        backer_size = backer_size / sizeof(struct backer);
    }

    /* Close the file. */
    fclose(backers);
}

if (backer_array) {
    for (i = 0; i < backer_size; i++) {
      /* Do stuff with backer_array[i]; */
    }
    free(backer_array); 
}

Answer 2

这是一个更好的代码。结构支持者和奖励的实例是指针：

struct backer_info {
    int backer_ID;
    char *backer_name[40];
    char *email[40];
    char *country[20];
} backer;

struct reward_info {
    int reward_number;
    int backer_ID;
    float price;
    int num_drones;
    int priority;
} reward; 

void load_data(){

    int i;
    int j;
    FILE *backers;
    FILE *rewards;

    struct backer_info *backer;

    if ((backers = fopen("backers.txt", "rb")) == NULL) {
        printf("File not found \n New  backers file created \n");
    }
    else{
        if (backer = malloc(sizeof(struct backer_info)) == NULL) {
             printf("Memory could't be allocated\n");
        for (i = 1; !feof(backers); i++) {
             fread(&backer, sizeof(struct backer_info), 1, backers);
             backer = realloc(backer, (i + 1) * sizeof(struct backer_info));
        }
        fclose(backers);
    }


    struct reward_info *reward;

    if ((rewards = fopen("rewards.txt", "rb")) == NULL) {
        printf("File not found \n, New rewards file created \n");
    }
    else{
        if (reward = malloc(sizeof(struct reward_info)) == NULL) {
             printf("Memory could't be allocated\n");
        }
        for (j = 1; !feof(rewards); j++) {
            fread(reward, sizeof(struct reward_info), 1, rewards);
            reward = realloc(reward, (i + 1) * sizeof(struct reward_info));
        }
        fclose(rewards);
    }
    /* Use the allocated space */
}

加载数据功能在C中需要帮助

2 个答案: