版权声明：本文为博主原创文章，未经博主允许不得转载。 https://blog.csdn.net/chenyefei/article/details/86508829
代码：
#include <stdio.h>
#include <string.h>
#include <stdint.h>
#include <stdlib.h>
/*
** 结构体中按照最长的一个成员变量大小对齐
**/
/**************************************
* | 1 | 2 |
* -------------
* | us1 |
* | us2 |
* | us3 |
* -------------
* 6
*/
struct A_S {
unsigned short us1;
unsigned short us2;
unsigned short us3;
};
/***************************************
* | 1 | 2 | 3 | 4 |
* -------------------------
* | uc | |
* | ui |
* | us | |
* -------------------------
* 12
*/
struct B_S {
unsigned char uc;
unsigned int ui;
unsigned short us;
};
/****************************************
* | 1 |
* -------
* | uc1 |
* | uc2 |
* | uc3 |
* -------
* 3
*/
struct C_S {
unsigned char uc1;
unsigned char uc2;
unsigned char uc3;
};
/****************************************
* | 1 | 2 | 3 | 4 |
* -------------------------
* | uc1 | |
* | ui |
* | uc2 | |
* -------------------------
* 12
*/
struct D_S {
unsigned char uc1;
unsigned int ui;
unsigned char uc2;
};
/****************************************
* | 1 | 2 |
* -------------
* | uc1 | |
* | us |
* | uc2 | |
* -------------
* 6
*/
struct E_S {
unsigned char uc1;
unsigned short us;
unsigned char uc2;
};
/****************************************
* | 1 | 2 | 3 | 4 |
* -------------------------
* | uc | | us1 |
* | us2 | |
* | ui |
* -------------------------
* 12
*/
struct F_S {
unsigned char uc;
unsigned short us[2];
unsigned int ui;
};
/****************************************
* | 1 | 2 | 3 | 4 |
* -------------------------
* | uc | | us |
* | ui |
* -------------------------
* 8
*/
struct G_S {
unsigned char uc;
unsigned short us;
unsigned int ui;
};
/****************************************
* | 1 | 2 | 3 | 4 |
* -------------------------
* | uc1 | |
* | d |
* | d |
* | uc2 | |
* -------------------------
* 16
*/
struct H_S {
unsigned char uc1;
double d;
unsigned char uc2;
};
struct TEST{
unsigned char uc1;
struct H_S hs;
unsigned char uc2;
};
int main(){
struct A_S as;
printf("sizeof(struct A_S)=%d\t",sizeof(struct A_S));
printf("us1=%p,us2=%p,us3=%p\n",&as.us1,&as.us2,&as.us3);
struct B_S bs;
printf("sizeof(struct B_S)=%d\t",sizeof(struct B_S));
printf("uc=%p,ui=%p,us=%p\n",&bs.uc,&bs.ui,&bs.us);
struct C_S cs;
printf("sizeof(struct C_S)=%d\t",sizeof(struct C_S));
printf("uc1=%p,uc2=%p,uc3=%p\n",&cs.uc1,&cs.uc2,&cs.uc3);
struct D_S ds;
printf("sizeof(struct D_S)=%d\t",sizeof(struct D_S));
printf("uc1=%p,ui=%p,uc2=%p\n",&ds.uc1,&ds.ui,&ds.uc2);
struct E_S es;
printf("sizeof(struct E_S)=%d\t",sizeof(struct E_S));
printf("uc1=%p,us=%p,uc2=%p\n",&es.uc1,&es.us,&es.uc2);
struct F_S fs;
printf("sizeof(struct F_S)=%d\t",sizeof(struct F_S));
printf("uc=%p,us1=%p,us2=%p,ui=%p\n",&fs.uc,&fs.us[0],&fs.us[1],&fs.ui);
struct G_S gs;
printf("sizeof(struct G_S)=%d\t",sizeof(struct G_S));
printf("uc=%p,us=%p,ui=%p\n",&gs.uc,&gs.us,&gs.ui);
struct H_S hs;
printf("sizeof(struct H_S)=%d\t",sizeof(struct H_S));
printf("uc1=%p,d=%p,uc2=%p\n",&hs.uc1,&hs.d,&hs.uc2);
printf("sizeof(struct TEST)=%d\n",sizeof(struct TEST));
return 0;
}结果：
$ ./test
sizeof(struct A_S)=6 us1=0xbfb56938,us2=0xbfb5693a,us3=0xbfb5693c
sizeof(struct B_S)=12 uc=0xbfb5694c,ui=0xbfb56950,us=0xbfb56954
sizeof(struct C_S)=3 uc1=0xbfb56935,uc2=0xbfb56936,uc3=0xbfb56937
sizeof(struct D_S)=12 uc1=0xbfb56958,ui=0xbfb5695c,uc2=0xbfb56960
sizeof(struct E_S)=6 uc1=0xbfb5693e,us=0xbfb56940,uc2=0xbfb56942
sizeof(struct F_S)=12 uc=0xbfb56964,us1=0xbfb56966,us2=0xbfb56968,ui=0xbfb5696c
sizeof(struct G_S)=8 uc=0xbfb56944,us=0xbfb56946,ui=0xbfb56948
sizeof(struct H_S)=16 uc1=0xbfb56970,d=0xbfb56974,uc2=0xbfb5697c
sizeof(struct TEST)=24