C++类成员布局

#include 
#include 
#include 

using namespace std;

class Concrete1 {
public:
void foo(void) {
cout <<"concrete1:" <}
Concrete1():val(1),bit1('a') {
}
public:
int val;
char bit1;
};

class Concrete2:public Concrete1 {
public:
char bit2;
public:
void foo(void) {
cout <<"concreate2" <}

Concrete2():bit2('b'),Concrete1() {
}
};

class Concrete3: public Concrete2 {
public:
void foo(void) {
cout <<"concrete3:" <}

Concrete3():bit3('c'),Concrete2() {
}

public:
char bit3;
};

template 
const char *access_order(data_type1 *mem1,data_type2 *mem2)
{
unsigned long p1,p2;

p1 = (unsigned long)(mem1);
p2 = (unsigned long)(mem2);

assert(p1 != p2);

return p1 ? "member 1 occurs first"
:"member 2 occurs first";
}


int main(int argc, char *argv[])
{
Concrete2 c2,*pc2;
Concrete1 c1,*pc1_1,*pc1_2;
Concrete3 c3;

pc2 = &c3;
pc1_1 = pc2;
pc1_2 = &c1;
char *b;

//access_order(&Concrete1::bit1,&Concrete1::bit);
cout <<"address val  and bit1:" <cout <<"Concrete3:" <
//b = *(char *)((char *)(&(pc1_2->bit1)) + 1);
b = &(pc1_2->bit1);

cout <<"Before address:" <(b) <<",b:" <<*b <b++;
cout <<"After address:" <(b) <cout <<"b:" <<*b <<"b+1:" <<*(b+1)<cout <<"Memberwise copy." <*pc1_2 = *pc1_1;
//b = *(char *)((char *)(&(pc1_2->bit1)) + 1);
b = &(pc1_2->bit1);

cout <<"Before address:" <(b) <<",b:" <<*b <b++;
cout <<"After address:" <(b) <cout <<"b:" <<*b <<"b+1:" <<*(b+1)<pc1_2->foo();


return 0;
}

f:\code\C++\study>concrete
concrete
address val  and bit1:member 1 occurs first
Concrete1:8//三个类大小均为8字节
Concrete2:8
Concrete3:8 
Before address:0x22ff34,b:a
After address:0x22ff35
b: b+1:"
Memberwise copy. //复制前后Concrete1对象填充字节内容未变化
Before address:0x22ff34,b:a
After address:0x22ff35
b: b+1:"
concrete1:a

testlayout
address val  and bit1:member 1 occurs first
Concrete1:8//三个类大小均不同，采用了对齐方式处理
Concrete2:12
Concrete3:16
Before address:0012FF40,b:a
After address:0012FF41
b:蘠+1:
Memberwise copy. //复制前后Concrete1对象填充字节内容未变化
Before address:0012FF40,b:a
After address:0012FF41
b:蘠+1:
concrete1:a