Question

我目前正在使用Arduino Uno，9DOF和XBee，我正在尝试创建一个可以通过串行，逐字节发送然后重新构造的结构进入结构。

到目前为止，我有以下代码：

struct AMG_ANGLES {
    float yaw;
    float pitch;
    float roll;
};

int main() {
    AMG_ANGLES struct_data;

    struct_data.yaw = 87.96;
    struct_data.pitch = -114.58;
    struct_data.roll = 100.50;

    char* data = new char[sizeof(struct_data)];

    for(unsigned int i = 0; i<sizeof(struct_data); i++){
        // cout << (char*)(&struct_data+i) << endl;
        data[i] = (char*)(&struct_data+i); //Store the bytes of the struct to an array.
    }

    AMG_ANGLES* tmp = (AMG_ANGLES*)data; //Re-make the struct
    cout << tmp.yaw; //Display the yaw to see if it's correct.
}

来源：http://codepad.org/xMgxGY9Q

此代码似乎不起作用，我不确定我做错了什么。

我该如何解决这个问题？

Answer 1

我似乎已用以下代码解决了我的问题。

struct AMG_ANGLES {
    float yaw;
    float pitch;
    float roll;
};

int main() {
    AMG_ANGLES struct_data;

    struct_data.yaw = 87.96;
    struct_data.pitch = -114.58;
    struct_data.roll = 100.50;

    //Sending Side
    char b[sizeof(struct_data)];
    memcpy(b, &struct_data, sizeof(struct_data));

    //Receiving Side
    AMG_ANGLES tmp; //Re-make the struct
    memcpy(&tmp, b, sizeof(tmp));
    cout << tmp.yaw; //Display the yaw to see if it's correct
}

警告：只有在发送和接收使用相同的endian架构时，此代码才有效。

Answer 2

你用错误的顺序做事，表达式

&struct_data+i

获取struct_data的地址，并将其增加i 乘以结构的大小。

请改为尝试：

*((char *) &struct_data + i)

这会将struct_data的地址转换为char *，然后然后添加索引，然后使用解除引用运算符（一元*）来获取那个地址的“char”。

Answer 3

始终充分利用数据结构..

union AMG_ANGLES {
  struct {
    float yaw;
    float pitch;
    float roll;
  }data;
  char  size8[3*8];
  int   size32[3*4];
  float size64[3*1];
};

Answer 4

for(unsigned int i = 0; i<sizeof(struct_data); i++){
    // +i has to be outside of the parentheses in order to increment the address
    // by the size of a char. Otherwise you would increment by the size of
    // struct_data. You also have to dereference the whole thing, or you will
    // assign an address to data[i]
    data[i] = *((char*)(&struct_data) + i); 
}

AMG_ANGLES* tmp = (AMG_ANGLES*)data; //Re-Make the struct
//tmp is a pointer so you have to use -> which is shorthand for (*tmp).yaw
cout << tmp->yaw; 
}

将struct转换为byte并返回struct

4 个答案: