Question

我正在尝试使用＆＃34; 00 00 00 00 00 00 00 A0＆＃34;分配字符缓冲区的前8字节。我能够验证缓冲区是否构造正确。每当我尝试使用我的实用程序进行hexdump时，我都会得到意想不到的输出。不确定，如果我在这里遗漏了别的东西。

#include<stdio.h>
#include<string.h>

static void hexdump(const char *src, int count)
{
    int i;  

    if (count == 0)
        return;

    for (i = 0; i < count; ++i) {

        printf("%02x ", src[i]);
        if ((i + 1) % 16 == 0)
            printf("\n");
    }   
    printf("\n");
}

int main() {
   char msg_buff[148];
   memset(msg_buff, 0, 148);
   int a[8] = {0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0xA0};
   sprintf(msg_buff, "%02x %02X %02X %02X %02X %02X %02X %02X", a[0], a[1], 
 a[2], a[3], a[4], a[5], a[6], a[7], a[8]);
   printf("packet %s \n", msg_buff); // 00 00 00 00 00 00 00 A0
   hexdump(msg_buff, 148);
}

我的输出

packet 00 00 00 00 00 00 00 A0 
30 30 20 30 30 20 30 30 20 30 30 20 30 30 20 30 
30 20 30 30 20 41 30 00 00 00 00 00 00 00 00 00 
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 
00 00 00 00

预期输出

packet 00 00 00 00 00 00 00 A0 
00 00 00 00 00 00 00 A0 00 00 00 00 00 00 00 00 
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 
00 00 00 00

Answer 1

首先，您需要从代码中的以下函数中删除a[8]，因为a[]的长度为8，但您的代码有9个成员：

sprintf(msg_buff, "%02X %02X %02X %02X %02X %02X %02X %02X", a[0], a[1], a[2], a[3], a[4], a[5], a[6], a[7], a[8]);

其次，您需要更改已定义的变量类型，您的代码应如下所示：

#include<stdio.h>
#include<string.h>

static void hexdump(const char *src, int count)
{
    int i;

    if (count == 0)
        return;

    for (i = 0; i < count; ++i) {

        printf("%02x ", src[i]);
        if ((i + 1) % 16 == 0)
            printf("\n");
    }
    printf("\n");
}

int main() {

    unsigned char  msg_buff[148];
    memset(msg_buff, 0, 148);
    unsigned char  a[8] = { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0xA0 };
    sprintf(msg_buff, "%02X %02X %02X %02X %02X %02X %02X %02X", a[0], a[1], a[2], a[3], a[4], a[5], a[6], a[7]);
    printf("packet %s \n", msg_buff); // 00 00 00 00 00 00 00 A0
    hexdump(msg_buff, 148);

    return 0;
}

Answer 2

更改 hexdump(msg_buff, 148);

要 hexdump(a, 8);

在您的代码中，您正在转储字符串

十六进制到char转换和转储输出

2 个答案: