继承

继承基本语法

提要点:class 子类 : 继承方式父类

//继承语法: class 自己定义的类(子类):继承方式 父类
#include<iostream>
using namespace std;
class Person
{
public:
    void body()
    {
        cout<<"Hello pretty girl"<<"\n";
    }
    void age1()
    {
        cout<<"19"<<"\n";
    }
};
class Alaso_shuang : public Person
{
public:
    void voice()
    {
        cout<<"interesting to listen"<<"\n";
    }
};
void test()
{
    Alaso_shuang Alaso;
    Alaso.age1();
    Alaso.body();
    Alaso.voice();
}
int main()
{
    test();
    return 0;
}

继承方式

提要点:
1.继承方式分为:公共继承(public)、保护继承(protected)、私有继承(private)
2.当子类以共有继承继承父类时,父类所有的对象(除了private)都是可以以共有继承形式访问
2.当子类以保护继承继承父类时,子类所有继承对象均以保护继承的形式出现，并且内外不能访问
3.当子类以私有继承继承父类时，子类所有继承对象均以私有继承的形式出现

#include<iostream>
using namespace std;
class F
{
public:
    int a;
protected:
    int b;
private:
    int c;
};
class F1
{
public:
    int a;
protected:
    int b;
private:
    int c;
};
class F2
{
public:
    int a;
protected:
    int b;
private:
    int c;
};
class son : public F
{
public:
    void f()
    {
        a = 10;//父类中公共权限成员拿到手了
    }
protected:
    void f1()
    {
        b = 20;
    }
// private:
//     void f3()
//     {
//         c = 1;//报错啦
//     }
};

class son1 : protected F1
{
protected:
    void f1()
    {
        a = 10;
        b = 40;
        //c = 90;//继续报错,说明父类隐私不允许访问
    }
};
class son2 : private F2
{
private:
    void f5()
    {
        a = 100;
        b = 300;
    }
};
void test01()
{
    son1 s;
}
int main()
{
    test01();
    return 0;
}

继承中对象模型

提要点:父类中所有对象均会被子类继承

#include<iostream>
using namespace std;
class f
{
public:
    int a;
protected:
    int b;
private:
    int c;
}; 
class son1:public f
{
    int a;
};
void solve()
{
    son1 s;
    cout<<"sizeof's value : "<< sizeof(s);
}
int main()
{
    solve();
    //答案是16,说明父类所有的成员都继承在了子类身上
    return 0;
}

继承同名成员处理方式

提要点:
1.访问子类同名成员(直接访问即可)
2.访问父类同名成员(需要加作用域)

#include<iostream>
using namespace std;
class F
{
public:
    F()
    {
        a = 10000;
    }
public:
    int a;
};
class son1 : public F
{

public:
    son1()
    {
        a = 2000000;
    }
    
public:
    int a;
};
void solve()
{
    son1 s;
    cout<<s.a<<"\n";
    F f;
    cout<<f.F::a<<"\n";//父类添加作用域
}
int main()
{
    solve();
    return 0;
}

多继承

提要点:语法:子类:public 父类1,public 父类2
(不建议使用该格式，会引来麻烦)

#include<iostream>
using namespace std;
class F1
{
public:
    F1()
    {
        m_A = 100000;
    }
public:
    int m_A;
};

class F2
{
public:
    F2()
    {
        m_B = 200000;
    }
    
public:
    int m_B;
};
class children : public F1,public F2//继承两个父类
{
public:
    int c_M;
    int d_M;
};
void test()
{
    children C;
    cout<<sizeof(C)<<"\n";
    cout<<C.m_A<<"\n";
    cout<<C.m_B<<"\n";
    //若是父类成员名称相同，就按照继承同名成员方式处理,直接加作用域即可
}
int main()
{
    test();
    return 0;
}