C语言中结构体与字符数组之间的相互转换

转载： https://blog.****.net/qq_31094099/article/details/80790346

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
 
#pragma  pack(push)  //保存对齐状态  
#pragma  pack(1)  
typedef struct strcChange
{
    unsigned char A;
    unsigned int B;
}STRU_CHANGE;
#pragma  pack(pop)  
 
 
 
//如果在未加字节对齐的情况下，那么A变量的后面需要自动填充三个字节，
//那么直接将结构体取地址后复制到另一个数组中，实际上所需占用的内存大小是8个byte。
 
typedef struct strcChange2
{
    unsigned char A;
    unsigned char B;
    unsigned char C;
}STRU_CHANGE2;
 
int main()
{
    STRU_CHANGE strChangeData1;
    STRU_CHANGE strChangeData2;
    STRU_CHANGE * pstrChangeData1;
    unsigned char * pucData;
 
    char C[10];
 
    strChangeData1.A = 0x01;
    strChangeData1.B = 0x05040302;
 
 
    strChangeData2.A = 0x11;
    strChangeData2.B = 0x55443322;
 
    pucData = (unsigned char *)(&strChangeData2);
 
    printf("pucData[0] = 0x%x\n", pucData[0]);
    printf("pucData[1] = 0x%x\n", pucData[1]);
    printf("pucData[2] = 0x%x\n", pucData[2]);
    printf("pucData[3] = 0x%x\n", pucData[3]);
    printf("pucData[4] = 0x%x\n", pucData[4]);
 
    memcpy(C, &strChangeData1, sizeof(strChangeData1));
 
    pstrChangeData1 = (STRU_CHANGE *)((char*)C);
 
    printf("STRU_CHANGE.A = 0x%x\n", pstrChangeData1->A);
    printf("STRU_CHANGE.B = 0x%08x\n", pstrChangeData1->B);
 
    system("PAUSE");
 
    return 0;
}

C语言中结构体与字符数组之间的相互转换

总结

服务端使用了 #pragma pack(n) ，客户端接收也必须同时对变量结构体进行 #pragma pack(n) 处理，不然对齐方式不同，直接赋值会错乱。

延伸阅读：
C语言的字节对齐及#pragma pack的使用 https://www.cnblogs.com/dabiao/archive/2010/04/15/1712458.html

C语言中结构体与字符数组之间的相互转换

总结

相关推荐