对一个程序的思考4（结构体内存对齐）

#include<stdio.h>#include<string.h>#pragma pack(4)int main(){unsigned char puc[4];struct tagPIM{unsigned char ucPim1;unsigned char ucData0 : 1;unsigned char ucData1 : 2;unsigned char ucData2 : 3;}*pstPimData;pstPimData = (struct tagPIM*)puc;memset(puc,0,4);pstPimData->ucPim1 = 2;pstPimData->ucData0 = 3;pstPimData->ucData1 = 4;pstPimData->ucData2 = 5;printf("%02x %02x %02x %02x\n",puc[0], puc[1], puc[2], puc[3]);return 0;}#pragma pack() /*恢复缺省对齐方式*/

先运行一下：

对于结果进行分析：