怪异的一个问题，完全不在知识范围内。今天弄DLL的，求解。

[zdrone]

代码：

#include "stdafx.h"

typedef struct tag_tg1
{
	//unsigned char	    f1;
	//unsigned char	    f2;
	//unsigned char	    f3;
	//unsigned char	    f4;
	//unsigned char	    f5;
	//int   	f6;
	double f7;
}tg1;

typedef struct tag_tg2
{
	//unsigned char	    f1;
	//unsigned char	    f2;
	//unsigned char	    f3;
	//unsigned char	    f4;
	//unsigned char	    f5;
	int   	f6;
	double f7;
}tg2;

typedef struct tag_tg3
{
	unsigned char	    f1;
	//unsigned char	    f2;
	//unsigned char	    f3;
	//unsigned char	    f4;
	//unsigned char	    f5;
	int   	f6;
	double f7;
}tg3;

typedef struct tag_tg4
{
	unsigned char	    f1;
	unsigned char	    f2;
	//unsigned char	    f3;
	//unsigned char	    f4;
	unsigned char	    f5;
	int   	f6;
	double f7;
}tg4;

typedef struct tag_tg5
{
	unsigned char	    f1;
	unsigned char	    f2;
	unsigned char	    f3;
	//unsigned char	    f4;
	unsigned char	    f5;
	int   	f6;
	double f7;
}tg5;

typedef struct tag_tg6
{
	unsigned char	    f1;
	unsigned char	    f2;
	unsigned char	    f3;
	unsigned char	    f4;
	unsigned char	    f5;
	int   	f6;
	double f7;
}tg6;

typedef struct tag_tg7
{
	unsigned char	    f1;
	unsigned char	    f2;
	unsigned char	    f3;
	unsigned char	    f4;
	unsigned char	    f5;
	int   	f6;
	int   	f7;
	double f8;
}tg7;

typedef struct tag_tg8
{
	unsigned char	    f1;
	unsigned char	    f2;
	unsigned char	    f3;
	unsigned char	    f4;
	unsigned char	    f5;
	int   	f6;
	int   	f7;
	double f8;
	double f9;
}tg8;

typedef struct tag_tg9
{
	unsigned char	    f1;
	unsigned char	    f2;
	unsigned char	    f3;
	unsigned char	    f4;
	unsigned char	    f5;
	int   	f6;
	int   	f7;
	double f8;
	double f9;
	char f10[20];
}tg9;


int main(int argc, char* argv[])
{
	printf("sizeof(unsigned char)=%d,sizeof(int)=%d,sizeof(double)=%d\n",sizeof(unsigned char),sizeof(int),sizeof(double));
	printf("sizeof(tg1)=%d,sizeof(tg2)=%d,sizeof(tg3)=%d,sizeof(tg4)=%d,sizeof(tg5)=%d,sizeof(tg6)=%d,sizeof(tg7)=%d,sizeof(tg8)=%d,sizeof(tg9)=%d\n",sizeof(tg1),sizeof(tg2),sizeof(tg3),sizeof(tg4),sizeof(tg5),sizeof(tg6),sizeof(tg7),sizeof(tg8),sizeof(tg9));
	
	return 0;
}

输出居然是:
sizeof(unsigned char)=1,sizeof(int)=4,sizeof(double)=8
sizeof(tg1)=8,sizeof(tg2)=16,sizeof(tg3)=16,sizeof(tg4)=16,sizeof(tg5)=16,sizeof(tg6)=24,sizeof(tg7)=24,sizeof(tg8)=32,sizeof(tg9)=56

完全无法理解，不在只是范围内，能不能有哪位大哥帮忙解释一下。

[fly_dragon_fly]

是8字节对齐不明白吗

[fefe82]

https://en.wikipedia.org/wiki/Data_structure_alignment

[paschen]

看完这个楼主就明白了：http://www.cnblogs.com/motadou/archive/2009/01/17/1558438.html

[大大大白]

这个涉及到内存的对齐与补齐的知识，你可以查一下

[cs_qd]

结构体字节对其嘛，网上搜一大片，都讲解得很清楚

[赵4老师]

仅供参考：

#include <stdio.h>
#define field_offset(s,f) (int)(&(((struct s *)(0))->f))
struct AD  { int a; char b[13]; double c;};
#pragma pack(push)
#pragma pack(1)
struct A1  { int a; char b[13]; double c;};
#pragma pack(2)
struct A2  { int a; char b[13]; double c;};
#pragma pack(4)
struct A4  { int a; char b[13]; double c;};
#pragma pack(8)
struct A8  { int a; char b[13]; double c;};
#pragma pack(16)
struct A16 { int a; char b[13]; double c;};
#pragma pack(pop)
int main() {
    printf("AD.a %d\n",field_offset(AD,a));
    printf("AD.b %d\n",field_offset(AD,b));
    printf("AD.c %d\n",field_offset(AD,c));
    printf("\n");
    printf("A1.a %d\n",field_offset(A1,a));
    printf("A1.b %d\n",field_offset(A1,b));
    printf("A1.c %d\n",field_offset(A1,c));
    printf("\n");
    printf("A2.a %d\n",field_offset(A2,a));
    printf("A2.b %d\n",field_offset(A2,b));
    printf("A2.c %d\n",field_offset(A2,c));
    printf("\n");
    printf("A4.a %d\n",field_offset(A4,a));
    printf("A4.b %d\n",field_offset(A4,b));
    printf("A4.c %d\n",field_offset(A4,c));
    printf("\n");
    printf("A8.a %d\n",field_offset(A8,a));
    printf("A8.b %d\n",field_offset(A8,b));
    printf("A8.c %d\n",field_offset(A8,c));
    printf("\n");
    printf("A16.a %d\n",field_offset(A16,a));
    printf("A16.b %d\n",field_offset(A16,b));
    printf("A16.c %d\n",field_offset(A16,c));
    printf("\n");
    return 0;
}
//AD.a 0
//AD.b 4
//AD.c 24
//
//A1.a 0
//A1.b 4
//A1.c 17
//
//A2.a 0
//A2.b 4
//A2.c 18
//
//A4.a 0
//A4.b 4
//A4.c 20
//
//A8.a 0
//A8.b 4
//A8.c 24
//
//A16.a 0
//A16.b 4
//A16.c 24
//
//