关于类初始化的问题 - 编程论坛

#2

鑫乐源2012-05-20 10:16

使类A做为虚基类

#3

JJ是也2012-05-20 17:01

回复 2楼鑫乐源

可以详细点吗？谢谢

#4

寒风中的细雨2012-05-20 18:47

程序代码：

#include <iostream>

using namespace std;

class A

{

public:
     A (int a)
     {
         cout << "\tEnter class A constructor..." << endl;
         cout << "Quit class A constructor..." << endl;
     }

};

class B : public A

{

public:
     B (int b) : A (b)
     {
         cout << "\tEnter class B constructor..." << endl;
         cout << "Quit class B constructor..." << endl;
     }

};

class C : public A

{

public:
     C (int c) : A (c)
     {
         cout << "\tEnter class C constructor..." << endl;
         cout << "Quit class C constructor..." << endl;
     }

};

class D : public B, public C

{

public:
     D (int d):C(d), B(d)
     {
         cout << "\tEnter class D constructor..." << endl;
         cout << "Quit class D constructor..." << endl;
     }

};

int main ()
{
    D d(1);
}

#5

JJ是也2012-05-21 17:16

回复 4楼寒风中的细雨

程序代码：

#include <iostream>
using namespace std;

class A
{
public:
     A (int a)
     {
         n = a;
         cout << "\tEnter class A constructor..." << endl;
         cout << "Quit class A constructor..." << endl;
     }
protected:
    int n;
};

class B : public A
{
public:
     B (int b) : A (b)
     {
         cout << "\tEnter class B constructor...    " << n << endl;
         cout << "Quit class B constructor..." << endl;
     }
};

class C : public A
{
public:
     C (int c) : A (c)
     {
         cout << "\tEnter class C constructor...    " << n << endl;
         cout << "Quit class C constructor..." << endl;
     }
};

class D : public B, public C
{
public:
     D (int d):B(d), C(d)
     {
         cout << "\tEnter class D constructor...    " << n << endl;    //为什么B类跟C类都可以调用A类的n，而D类不能用A类的n？
         cout << "Quit class D constructor..." << endl;
     }
};

int main ()
{
    D d(28);
}

高手请指点

#6

lknight2012-05-22 21:25

b和c都继承了a，都存在n，d再继承b和c时，n就有两份，d在访问n时就产生歧义了，不知道访问的是哪个是d->b->a还是d->c->a了。

#7

JJ是也2012-05-23 21:50

回复 6楼 lknight

那请问我可以怎样编写才能用到基类的n，高手请指点

#8

lknight2012-05-24 18:33

程序代码：

#include <iostream>
using namespace std;

class A
{
public:
     A (int a)
     {
         n = a;
         cout << "\tEnter class A constructor..." << endl;
         cout << "Quit class A constructor..." << endl;
     }
protected:
    int n;
};

class B : public virtual A
{
public:
     B (int b) : A (b)
     {
         cout << "\tEnter class B constructor...    " << n << endl;
         cout << "Quit class B constructor..." << endl;
     }
};

class C : public virtual A
{
public:
     C (int c) : A (c)
     {
         cout << "\tEnter class C constructor...    " << n << endl;
         cout << "Quit class C constructor..." << endl;
     }
};

class D : public B, public C
{
public:
     D (int d):B(d), C(d),A(d)

     {
         cout << "\tEnter class D constructor...    " << n << endl;
         cout << "Quit class D constructor..." << endl;
     }
};

int main ()
{
    D d(28);
    return 0;
}

#9

JJ是也2012-05-27 10:33

回复 8楼 lknight

太感谢了