C++ 程序错误分析：计算机类构造函数、RAM 和 CDROM 类初始化问题

以下是一个 C++ 程序，请告诉我错误在哪里？

#pragma once
#include<iostream>
#include<string.h>
using namespace std;

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

class CPU {
private:
	CPU_Rank rank;
	int CPU_frequency;
	double CPU_voltage;
public:
	CPU(int newRank, int newFrequency, int newVoltage)
	{
		rank = (CPU_Rank)newRank;
		CPU_frequency = newFrequency;
		CPU_voltage = newVoltage;
	};
	CPU()//构造函数重载
	{
		rank = P6;
		CPU_frequency = 3000;
		CPU_voltage = 220;
	}
	~CPU()
	{
		cout << 'Good bye!' << endl;
	}
	CPU(const CPU& p)
	{
		rank = p.rank;
		CPU_frequency = p.CPU_frequency;
		CPU_voltage = p.CPU_voltage;
	};
	CPU_Rank outRank() { return rank;};
	int outF() { return CPU_frequency; };
	double outV() { return CPU_voltage; };
};

class RAM {
private:
	string name;
	int RAM_frequency;
	int RAM_capacity;
public:
	RAM(string Name, int a, int b)
	{
		name = Name;
		RAM_frequency = a;
		RAM_capacity = b;
	};
	RAM()
	{
		name = '未知';
		RAM_frequency = NULL;
		RAM_capacity = NULL;
	}
	~RAM()
	{
		cout << 'Good bye!' << endl;
	}
};

class CDROM {
private:
	string Cname;
	int speed;
public:
	CDROM(string CName, int Cspeed)
	{
		Cname = CName;
		speed = Cspeed;
	};
	CDROM()
	{
		Cname = '未知';
		speed = NULL;
	};

};

class Computer :public CPU,public RAM,public CDROM{

public:
	Computer(int a, int b, int c, string* N, int d, int e, string* M, int f) :CPU(a, b, c), RAM(*N, d, e), CDROM(*M, f) {};
	void run() { cout << 'Computer开始运行！' << endl; }
	void stop() { cout << 'Computer停止运行！' << endl; };
	void output1() 
	{  
		cout << '我是组装机' << endl;
		cout << 'CPU:' << endl;
		cout << '等级:' << outRank() << '\n' << '频率：' << outF() << '\n' << '电压：' << outV() << endl;
		
		
		
	};
};

int main()
{
	cout << '请按顺序输入一台组装机芯片(等级、频率、电压)、内存(品牌、主频、容量）、光驱参数(品牌、传输速率)：' << endl;

	int newrank, newfrequency, newvoltage;
	cin >> newrank >> newfrequency >> newvoltage;

	string Name;
	int RAM_frequency,RAM_capacity;
	cin >> Name >> RAM_frequency >> RAM_capacity;

	string CName;
	int Cspeed;
	cin >> CName >> Cspeed;

	Computer A (int newrank, int newfrequency, int newvoltage, string Name, int RAM_frequency, int RAM_capacity, string CName, int Cspeed);
	
	cout << '等级:' << A.outRank() << endl;
	



	return 0;
}

以下是错误：

在 Computer 类的构造函数中，应该使用参数而不是变量类型：

Computer(int a, int b, int c, string* N, int d, int e, string* M, int f) :CPU(a, b, c), RAM(*N, d, e), CDROM(*M, f) {};

在 Computer 类的构造函数调用中，不应该使用变量类型：

Computer A(int newrank, int newfrequency, int newvoltage, string Name, int RAM_frequency, int RAM_capacity, string CName, int Cspeed);

应该改为：

Computer A(newrank, newfrequency, newvoltage, &Name, RAM_frequency, RAM_capacity, &CName, Cspeed);

RAM 类的构造函数中，应该使用 nullptr 而不是 NULL：

RAM()
{
    name = '未知';
    RAM_frequency = nullptr;
    RAM_capacity = nullptr;
}

CDROM 类的构造函数中，应该使用 0 而不是 NULL：

CDROM()
{
    Cname = '未知';
    speed = 0;
}