C语言读取通达信数据

因为无法事先知道数据的行数，只能通过计算得到，所以数组创建只能通过动态分配内存。

一个解决方案是，我只想读取最后1000行，那么数组就可以直接定义大小为1000，然后把文件指针定位到倒数1000行。

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

struct Stock {
    int date;
    float open;
    float high;
    float low;
    float close;
    float amount;
    int volume;
    int reserved;
};

int main() {
    FILE *fp = fopen("sz000001.day", "rb");
    if (fp == NULL) {
        perror("Error opening file");
        return -1;
    }
    fseek(fp, 0, SEEK_END);          // 定位文件末尾
    long file_size = ftell(fp);      // 获取文件大小
    int line_count = file_size / 32; // 计算行数（假设每行32字节）
    fseek(fp, 0, SEEK_SET);          // 回到文件开头
    // 动态分配内存
    struct Stock *stockArr = malloc(line_count * sizeof(struct Stock));
    if (stockArr == NULL) {
        perror("Error allocating memory");
        return -1;
    }
    int date, open, high, low, close, volume, reserved;
    float amount;
    int i = 0;
    for (int i = 0; i < line_count; i++) {
        // 读取数据
        fread(&date, 4, 1, fp);
        fread(&open, 4, 1, fp);
        fread(&high, 4, 1, fp);
        fread(&low, 4, 1, fp);
        fread(&close, 4, 1, fp);
        fread(&amount, 4, 1, fp);
        fread(&volume, 4, 1, fp);
        fread(&reserved, 4, 1, fp);

        // printf("Date: %d, Open: %d, High: %d, Low: %d, Close: %d, Amount: %f, Volume: %d, Reserved: %d\n", date, open, high, low, close, amount,
        //        volume, reserved);
        stockArr[i].date = date;
        stockArr[i].open = open / 100.0;
        stockArr[i].high = high / 100.0;
        stockArr[i].low = low / 100.0;
        stockArr[i].close = close / 100.0;
        stockArr[i].amount = amount / 10000.0;
        stockArr[i].volume = volume;
        stockArr[i].reserved = reserved;

        // printf("Date: %d, Open: %.2f, High: %.2f, Low: %.2f, Close: %.2f, Amount: %.2f, Volume: %d, Reserved: %d\n", stockArr[i].date,
        //        stockArr[i].open, stockArr[i].high, stockArr[i].low, stockArr[i].close, stockArr[i].amount, stockArr[i].volume, stockArr[i].reserved);
    }
    printf("%d", stockArr[line_count-1].date);

    free(stockArr); // 释放动态分配的内存
    fclose(fp);     // 释放文件

    return 0;
}