#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#pragma pack(push)
#pragma pack(1)
typedef struct strcChange
{
unsigned int B;
unsigned short C;
unsigned char A;
}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。*/
int main()
{
int i;
STRU_CHANGE strChangeData1;
STRU_CHANGE strChangeData2;
STRU_CHANGE strChangeData3;
STRU_CHANGE * pstrChangeData1;
unsigned char * pucData;
char C[10];
strChangeData2.A = 0x11;
strChangeData2.B = 0x55443322;
strChangeData2.C = 0x000b;
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]);
printf("pucData[4] = 0x%x\n", pucData[5]);
printf("pucData[4] = 0x%x\n", pucData[6]);
/*结构体转字符串*/
strChangeData1.A = 0x01;
strChangeData1.B = 0x05040302;
strChangeData1.C = 0x000a;
memcpy(C, &strChangeData1, sizeof(strChangeData1));
for(i = 0; i < strlen(C); i++)
{
printf("C %x\n", C[i]);
}
/* 字符串转结构体*/
pstrChangeData1 = (STRU_CHANGE *)C;
printf("STRU_CHANGE.A = 0x%x\n", pstrChangeData1->A);
printf("STRU_CHANGE.B = 0x%08x\n", pstrChangeData1->B);
printf("STRU_CHANGE.C = 0x%04x\n", pstrChangeData1->C);
/* 字符串转结构体*/
memcpy(&strChangeData3, C, sizeof(C));
printf("STRU_CHANGE.A = 0x%x\n", strChangeData3.A);
printf("STRU_CHANGE.B = 0x%08x\n", strChangeData3.B);
printf("STRU_CHANGE.C = 0x%04x\n", strChangeData3.C);
return 0;
}
root@ubuntu:/home/share/test# ./app
pucData[0] = 0x22
pucData[1] = 0x33
pucData[2] = 0x44
pucData[3] = 0x55
pucData[4] = 0xb
pucData[4] = 0x0
pucData[4] = 0x11
C 2
C 3
C 4
C 5
C a
STRU_CHANGE.A = 0x1
STRU_CHANGE.B = 0x05040302
STRU_CHANGE.C = 0x000a
STRU_CHANGE.A = 0x1
STRU_CHANGE.B = 0x05040302
STRU_CHANGE.C = 0x000a