C++多继承（多重继承）详解

多继承容易让代码逻辑复杂、思路混乱，一直备受争议，中小型项目中较少使用，后来的 Java、C#、PHP 等干脆取消了多继承。

class D: public A, private B, protected C{
    //类D新增加的成员
}

多继承下的构造函数

D(形参列表): A(实参列表), B(实参列表), C(实参列表){
    //其他操作
}

D(形参列表): B(实参列表), C(实参列表), A(实参列表){
    //其他操作
}

#include <iostream>
using namespace std;

//基类
class BaseA{
public:
    BaseA(int a, int b);
    ~BaseA();
protected:
    int m_a;
    int m_b;
};
BaseA::BaseA(int a, int b): m_a(a), m_b(b){
    cout<<"BaseA constructor"<<endl;
}
BaseA::~BaseA(){
    cout<<"BaseA destructor"<<endl;
}

//基类
class BaseB{
public:
    BaseB(int c, int d);
    ~BaseB();
protected:
    int m_c;
    int m_d;
};
BaseB::BaseB(int c, int d): m_c(c), m_d(d){
    cout<<"BaseB constructor"<<endl;
}
BaseB::~BaseB(){
    cout<<"BaseB destructor"<<endl;
}

//派生类
class Derived: public BaseA, public BaseB{
public:
    Derived(int a, int b, int c, int d, int e);
    ~Derived();
public:
    void show();
private:
    int m_e;
};
Derived::Derived(int a, int b, int c, int d, int e): BaseA(a, b), BaseB(c, d), m_e(e){
    cout<<"Derived constructor"<<endl;
}
Derived::~Derived(){
    cout<<"Derived destructor"<<endl;
}
void Derived::show(){
    cout<<m_a<<", "<<m_b<<", "<<m_c<<", "<<m_d<<", "<<m_e<<endl;
}

int main(){
    Derived obj(1, 2, 3, 4, 5);
    obj.show();
    return 0;
}

命名冲突

#include <iostream>
using namespace std;

//基类
class BaseA{
public:
    BaseA(int a, int b);
    ~BaseA();
public:
    void show();
protected:
    int m_a;
    int m_b;
};
BaseA::BaseA(int a, int b): m_a(a), m_b(b){
    cout<<"BaseA constructor"<<endl;
}
BaseA::~BaseA(){
    cout<<"BaseA destructor"<<endl;
}
void BaseA::show(){
    cout<<"m_a = "<<m_a<<endl;
    cout<<"m_b = "<<m_b<<endl;
}

//基类
class BaseB{
public:
    BaseB(int c, int d);
    ~BaseB();
    void show();
protected:
    int m_c;
    int m_d;
};
BaseB::BaseB(int c, int d): m_c(c), m_d(d){
    cout<<"BaseB constructor"<<endl;
}
BaseB::~BaseB(){
    cout<<"BaseB destructor"<<endl;
}
void BaseB::show(){
    cout<<"m_c = "<<m_c<<endl;
    cout<<"m_d = "<<m_d<<endl;
}

//派生类
class Derived: public BaseA, public BaseB{
public:
    Derived(int a, int b, int c, int d, int e);
    ~Derived();
public:
    void display();
private:
    int m_e;
};
Derived::Derived(int a, int b, int c, int d, int e): BaseA(a, b), BaseB(c, d), m_e(e){
    cout<<"Derived constructor"<<endl;
}
Derived::~Derived(){
    cout<<"Derived destructor"<<endl;
}
void Derived::display(){
    BaseA::show();  //调用BaseA类的show()函数
    BaseB::show();  //调用BaseB类的show()函数
    cout<<"m_e = "<<m_e<<endl;
}

int main(){
    Derived obj(1, 2, 3, 4, 5);
    obj.display();
    return 0;
}

• Java都学哪些课程_数据库
• MySQL查询不重复单位,专精Oracle还是MySQL_数据库
• mysql嵌套查询临时表,oracle是计算机高级语言吗_数据库
• SQL函数substr使用简介_数据库
• 网页端嵌入mysql查询,mysql怎么跨数据库查询信息_数据库
• mysql查询客户信息,sql语句查询mysql怎么取前几天的数据_数据
• 怎样安装数据库_数据库
• link接口插什么线_数据库
• mysql库级别锁死怎么解决_数据库
• 树莓派下python连接mysql_数据库
• 计算机二级科目怎么选_数据库
• 查询mysql登录情况,mysql忘记root密码怎么登录_数据库
• mysql子查询约束,mysql设置唯一的属性怎么取消_数据库
• 数据库类型怎么查看_数据库
• python程序进程挂掉_数据库
• 如何把Linux的性能调整到最佳状态_数据库
• mysql子查询条件判断,mysql如何查询字符串中其中一位_数据库
• mysql子查询统计排序,mysql怎么增加一列显示行数_数据库
• Django怎样直接生成数据表_数据库
• mysql分组带模糊查询,自学网络编程能被程序员驿站签约吗_数据库