第11周-程序阅读1-3-多重继承

最新推荐文章于 2022-02-25 22:31:36 发布

原创最新推荐文章于 2022-02-25 22:31:36 发布 · 645 阅读

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#C++ #继承 #对象 #类 #阅读

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本文通过三个示例深入探讨了C++中多重继承的构造过程、虚基类的使用及其如何解决菱形继承问题。示例包括成员函数重写、构造函数调用流程及虚基类的实例化。

问题及代码：

#include <iostream>  
using namespace std;  
class A  
{  
public:  
    A()  
    {  
        a=0;  
    }  
    A (int i)  
    {  
        a=i;  
    }  
    void print()  
    {  
        cout<<a<<"  ";  
    }  
private:  
    int a;  
};  
class B: public A  
{  
public:  
    B()  
    {  
        b=0;  
    }  
    B(int i, int j, int k): A(i),aa(j)  
    {  
        b=k;  
    }  
    //思考：这3处出现的print，有何区别  
    void print()      //(1)  
    {  
        A::print();   //(2)  
        aa.print();   //(3)  
        cout<<b<<endl;  
    }  
private:  
    int b;  
    A aa;  
};  
int main()  
{  
    B test[2];  
    test[0]=B(1,4,7);  
    test[1]=B(2,5,8);  
    for(int i=0; i<2; i++)  
        test[i].print();  
    return 0;  
}

运行结果：

问题及代码：

#include <iostream>  
using namespace std;  
class A  
{  
public:  
    A(char *s)  
    {  
        cout<<s<<endl;  
    }  
};  
class B:public A  
{  
public:  
    B(char *s1, char *s2):A(s1)  
    {  
        cout<<s2<<endl;  
    }  
};  
class C:public A  
{  
public:  
    C(char *s1,char *s2):A(s1)  
    {  
        cout<<s2<<endl;  
    }  
};  
class D:public B, C  
{  
public:  
    D(char *s1,char *s2,char *s3,char *s4):B(s1,s2),C(s3,s4)  
    {  
        cout<<s4<<endl;  
    }  
};  
int main()  
{  
    D d("class A","class B","class C","class D");  
    return 0;  
}

运行结果：

问题及代码：

#include <iostream>  
using namespace std;  
class Base  
{  
public:  
    Base(char i) { cout<<"Base constructor. --"<<i<<endl; }  
};  
class Derived1:virtual public Base  
{  
public:  
    Derived1(char i,char j):Base(i)  
    {  
        cout<<"Derived1 constructor. --"<<j<<endl;  
    }  
};  
class Derived2:virtual public Base  
{  
public:  
    Derived2(char i,char j):Base(i)  
    {  
        cout<<"Derived2 constructor. --"<<j<<endl;  
    }  
};  
class MyDerived:public Derived1,public Derived2  
{  
public:  
    MyDerived(char i,char j,char k,char l,char m,char n,char x): Derived2(i,j), Derived1(k,l), Base(m), d(n)  
    {  
        cout<<"MyDerived constructor. --"<<x<<endl;  
    }  
private:  
    Base d;  
};  
int main()  
{  
    MyDerived obj('A','B','C','D','E','F','G');  
    return 0;  
}

运行结果：