如何使用fread和fwrite函数来读写二进制文件？

Question

嗨,在我的项目中,我要读取一个.bin文件,其中包含传感器数据short(16 bit values).我正在使用fread函数进入缓冲区,但我觉得读入没有正确发生.我的意思是我写的东西和我读的东西之间没有一致性.你们能否说出这里出了什么问题？这不是我项目中的代码......我只想在这里验证fread和fwrite功能.

#include<stdio.h>
void main()
{
    FILE *fp = NULL;

    short x[10] = {1,2,3,4,5,6,5000,6,-10,11};
    short result[10];

    fp=fopen("c:\\temp.bin", "wb");

    if(fp != NULL)
    {
        fwrite(x, 2 /*sizeof(short)*/, 10 /*20/2*/, fp);
        rewind(fp);
        fread(result, 2 /*sizeof(short)*/, 10 /*20/2*/, fp);
    }
    else
        exit(0);

    printf("\nResult");
    printf("\n%d",result[0]);
    printf("\n%d",result[1]);
    printf("\n%d",result[2]);
    printf("\n%d",result[3]);
    printf("\n%d",result[4]);
    printf("\n%d",result[5]);
    printf("\n%d",result[6]);
    printf("\n%d",result[7]);
    printf("\n%d",result[8]);
    printf("\n%d",result[9]);

    fclose(fp)
 }

我做了fread()(HEX值)后:

temp.bin:
01 02 03 04 05 06 e1 8e 88 06 ef bf b6 0b...

我做了fwrite()之后

stdout:
Result
0
914
-28
-28714
-32557
1
512
-32557
908
914

Answer 1

用模式打开文件w+(读写).以下代码有效:

#include<stdio.h>
int main()
{
    FILE *fp = NULL;

    short x[10] = {1,2,3,4,5,6,5000,6,-10,11};
    short result[10];
    int i;

    fp=fopen("temp.bin", "w+");

    if(fp != NULL)
    {
        fwrite(x, sizeof(short), 10 /*20/2*/, fp);
        rewind(fp);
        fread(result, sizeof(short), 10 /*20/2*/, fp);
    }
    else
        return 1;

    printf("Result\n");
    for (i = 0; i < 10; i++)
        printf("%d = %d\n", i, (int)result[i]);

    fclose(fp);
    return 0;
}

随着输出:

Result
0 = 1
1 = 2
2 = 3
3 = 4
4 = 5
5 = 6
6 = 5000
7 = 6
8 = -10
9 = 11