Question

我正在尝试编写一个程序来从二进制文件中获取输入，该文件中包含交替的Altitude和Airspeed数字的数据点，并将其转换为csv文件。数据需要从big endian到little endian的字节转换。当我运行我的代码时，我得到所有这些代码的相同数字，并且它不是用于打印输出的正确数字，并且除了奇怪的希腊字母之外它不会打印到csv文件。有人能告诉我我做错了什么吗？

代码：

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

int main()
{
union byteswap
{
    char c_num[4];
    float f_num;
};
char temp;
union byteswap data;
int size;
int i;
struct time
{
    //float time_s;
    float Alt_ft;
    float AS_knots;
    //float mach_number;
};
struct time time_pt;
FILE *fp;
fp = fopen("C:\\Users\\daxon\\eclipse-workspace\\Flight-Data-Proj\\Alt_AS.dat", "r+b");

FILE *csv;
csv = fopen("C:\\Users\\daxon\\eclipse-workspace\\Flight-Data-Proj\\Flight-Data.csv", "w+");

if (fp== NULL)
{
    fprintf(stderr, "Data file would not open");
    return(-1);
}

fseek(fp, 0, SEEK_END);
size=ftell(fp);
fprintf(stdout, "The size of the file is %d\n", size);
fseek(fp,0,SEEK_CUR);

    for (i = 0; i<= feof(fp); i++)
    {
        fread(&time_pt, 8, 1, fp);
        fprintf(stdout, "Uswapped is %d\n", time_pt);

        //byte swap
        temp = data.c_num[0];
        data.c_num[0] = data.c_num[3];
        data.c_num[3]= temp;
        temp = data.c_num[1];
        data.c_num[1] = data.c_num[2];
        data.c_num[2]= temp;

        printf("Alt is %f,  AS is %f\n", time_pt.Alt_ft, time_pt.AS_knots);
        fwrite(&time_pt.Alt_ft, 4, 1, csv);
        fwrite(&time_pt.AS_knots, 4, 1, csv);
    }

fclose(fp);
fclose(csv);
fprintf(stdout, "Done reading files\n");
return 0;

}

输出：

文件大小为143208 Uswapped是1986426061