子类拷贝构造函数的问题【拜托各位看下】

[mabo321]

class Prototype
{
public:
	Prototype(string st)
	{
		str = st;
	}
	string Get()
	{
		return str;
	}

	virtual Prototype * Clone()=0;
	virtual ~Prototype(){}
private:
	string str;
};


class ConcretePrototype1 : public Prototype
{
public:
	ConcretePrototype1(string st) : Prototype(st)
	{
	}
	ConcretePrototype1(const ConcretePrototype1 & proto)  // 就这块，提示父类Prototype没有默认构造。
	{
		member = proto.member;
		cout << " ConcretePrototype1 Copy  ... " <<endl;
	}
	Prototype * Clone()
	{
		member = new ConcretePrototype1(*this);
		return member;
	}

	~ConcretePrototype1()
	{}
private:
	ConcretePrototype1 * member;
};

如果我在 父类Prototype中加一个默认构造 ，那么 Clone()函数拷贝出来的对象 的Get()值是空的啊……（可是我想的是 连父类的属性一起拷贝啊）

小弟我应该怎么弄啊……各位大虾，拜托指点一二……不胜感激

[星羽]

class Prototype
{
public:
    Prototype(string st)
    {
        str = st;
    }
    string Get()
    {
        return str;
    }

    virtual Prototype * Clone()=0;
    virtual ~Prototype(){}
protected:
    string str;
};


class ConcretePrototype1 : public Prototype
{
public:
    ConcretePrototype1(string st) : Prototype(st)
    {
    }
    ConcretePrototype1(const ConcretePrototype1 & proto)  // 就这块，提示父类Prototype没有默认构造。
        : Prototype(proto.str)
    {
        member = proto.member;
        cout << " ConcretePrototype1 Copy  ... " <<endl;
    }
    Prototype * Clone()
    {
        member = new ConcretePrototype1(*this);
        return member;
    }

    ~ConcretePrototype1()
    {}
private:
    ConcretePrototype1 * member;
};

[baihacker]

ConcretePrototype1(const ConcretePrototype1 & proto) 要和
ConcretePrototype1(string st) : Prototype(st)
类似处理一下

[waizqfor]

class Prototype
{
public:
    Prototype(string st)
    {
        str = st;
    }
    string Get()
    {
        return str;
    }

    virtual Prototype * Clone()=0;
    virtual ~Prototype(){}
private:
    string str;
};


class ConcretePrototype1 : public Prototype
{
public:
    ConcretePrototype1(string st) : Prototype(st)
    {
    }
    ConcretePrototype1(const ConcretePrototype1 & proto):Prototype(st)  // 就这块，提示父类Prototype没有默认构造。
    {
        member = proto.member;
        cout << " ConcretePrototype1 Copy  ... " <<endl;
    }
    Prototype * Clone()
    {
        member = new ConcretePrototype1(*this);
        return member;
    }

    ~ConcretePrototype1()
    {}
private:
    ConcretePrototype1 * member;
};

[OenAuth.Core]

星羽哥，飞雪兄，该睡觉啦

[malganis00]

认真看一下书
！！

[oyljerry]

初始化列表，把str初始化你的父类

[xiaoyisnail]

子类如果没有显示调用父类的构造函数初始化父类部分的话，编译器会尝试调用父类的默认构造函数来初始化父类部分，由于你没有为父类提供默认构造函数，所以错了

[OenAuth.Core]

拷贝构造也是构造函数，应该采用初始化成员列表的形式把父类的也加上

[xiaoyisnail]

#include <string>
#include <iostream>
using namespace std;

class Prototype
{
public:
    Prototype(string st)
    {
        str = st;
    }
    string Get()
    {
        return str;
    }

    virtual Prototype * Clone()=0;
    virtual ~Prototype(){}
private:
    string str;
};


class ConcretePrototype1 : public Prototype
{
public:
    ConcretePrototype1(string st) : Prototype(st)
    {
    }
    ConcretePrototype1(const ConcretePrototype1 & proto):Prototype("") //可以这样用空串来初始化
    {
        member = proto.member;
        cout << " ConcretePrototype1 Copy  ... " <<endl;
    }
    Prototype * Clone()
    {
        member = new ConcretePrototype1(*this);
        return member;
    }

    ~ConcretePrototype1()
    {}
private:
    ConcretePrototype1 * member;
};

[xiaoyisnail]

#include <string>
#include <iostream>
using namespace std;

class Prototype
{
public:
	Prototype():str(""){}//或者这样为父类提供一个默认构造函数
    Prototype(string st)
    {
        str = st;
    }
    string Get()
    {
        return str;
    }

    virtual Prototype * Clone()=0;
    virtual ~Prototype(){}
private:
    string str;
};


class ConcretePrototype1 : public Prototype
{
public:
    ConcretePrototype1(string st) : Prototype(st)
    {
    }
    ConcretePrototype1(const ConcretePrototype1 & proto)
    {
        member = proto.member;
        cout << " ConcretePrototype1 Copy  ... " <<endl;
    }
    Prototype * Clone()
    {
        member = new ConcretePrototype1(*this);
        return member;
    }

    ~ConcretePrototype1()
    {}
private:
    ConcretePrototype1 * member;
};

[OenAuth.Core]

晕，一下子卡到8楼来了，

呵呵，这种编译器会自己提示错误的，不过你要是自己加了一个默认的构造，如
Prototype()
{
str ="";
}
那就麻烦了，呵呵。

[mabo321]

class Prototype
{
public:
    Prototype(string st)
    {
        str = st;
    }
    string Get()
    {
        return str;
    }

    virtual Prototype * Clone()=0;
    virtual ~Prototype(){}
private:
    string str;
};


class ConcretePrototype1 : public Prototype
{
public:
    ConcretePrototype1(string st) : Prototype(st)
    {
    }
    ConcretePrototype1(ConcretePrototype1 & proto) : Prototype(proto.Get()) // 这样可以，我脑子唬住了0_o (星雨大哥的不能访问私有成员)
    {                                             
        member = proto.member;
        cout << " ConcretePrototype1 Copy  ... " <<endl;
    }
    Prototype * Clone()
    {
        member = new ConcretePrototype1(*this);
        return member;
    }

    ~ConcretePrototype1()
    {}
private:
    ConcretePrototype1 * member;
};

谢谢各位……