C++的小发现 请大家帮忙看看 对么 书本和实践是有差距的

//2. 定义一个简单的Computer类，有数据成员芯片（cpu）、内存（ram）、光驱（cdrom）等等，

//有两个公有成员函数run、stop。cpu为CPU类的一个对象，ram为RAM类的一个对象，

//cdrom为CDROM类的一个对象，定义并实现这个类。

#include<iostream>

using namespace std;

enum CPU_Rank{P1=1,P2,P3,P4,P5,P6,P7};

class CPU

{

public:

CPU(CPU_Rank x,int y,float z)

{

rank=x;

frequency=y;

voltage=z;

cout<<"cpu create"<<endl;

}

CPU(CPU &c);

~CPU(){cout<<"cpu reset"<<endl;}

private:

CPU_Rank rank;

int frequency;

float voltage;

};

CPU::CPU(CPU &c)

{

rank=c.rank;

frequency=c.frequency;

voltage=c.voltage;

cout<<"cpu copy"<<endl;

}

class RAM

{

public:

RAM(int x=1)

{

ram=x;

cout<<"ram create"<<endl;

}

RAM(RAM &r);

~RAM(){cout<<"RAM reset"<<endl;}

private:

int ram;

};

RAM::RAM(RAM &r)

{

ram=r.ram;

cout<<"ram copy"<<endl;

}

class CDROM

{

public:

CDROM(int m)

{

cdrom=m;

cout<<"CD create "<<endl;

}

CDROM(CDROM &d);

~CDROM (){cout<<"CD reset"<<endl;}

private:

int cdrom;

};

CDROM::CDROM(CDROM &d)

{

cdrom=d.cdrom;

cout<<"cdrom copy"<<endl;o

}

class Computer

{

public:

Computer(CPU x,RAM y,CDROM z);

Computer(Computer &p);

~Computer(){cout<<"computer reset"<<endl;}

private:

CPU cpu;

RAM ram;

CDROM cdrom;

};

Computer::Computer(CPU x,RAM y,CDROM z):cpu(x),ram(y),cdrom(z)

{

cout<<"Computer create1"<<endl;

}

Computer::Computer(Computer &p):cpu(p.cpu),ram(p.ram),cdrom(p.cdrom)

{

cout<<"computer copy"<<endl;

}

int main (void)

{

CPU a(P1,2,3);

RAM b(3);

CDROM c(4);

Computer d(a,b,c);

Computer e(d);

return 0;

}

//书上讲的 调用内嵌对象的构造函数，调用顺序和定义的时候一样， 可是结果相反。

大家帮忙看看 我猜想是因为栈空间的影响 求大牛