C++ Primer Plus 学习笔记第十三章类继承

秒速五厘米 2022-01-26 09:47 215阅读 0赞

继承格式

class A ：parent B

派生类要有自己的构造函数

可以根据需要添加额外的数据成员和成员函数

![2019052818264935.png][]

![20190528182655636.png][]

![20190528182704847.png][]

![2019052818271588.png][]

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3NvdWx3eWI_size_16_color_FFFFFF_t_70][]

继承的例子：

tabtenn1.h

#ifndef TABTENN1_H_
    #define TABTENN1_H_
    
    #include <string>
    using std::string;
    class TableTennisPlayer
    {
      private:
        string firstname;
        string lastname;
        bool hasTable;
      public:
        TableTennisPlayer(const string & fn = "none",
                          const string & ln = "none", bool ht = false);
        void Name() const;
        bool HasTable() const {return hasTable;}
        void ResetTable(bool v) {hasTable = v;}
    };
    
    class RatedPlayer : public TableTennisPlayer
    {
      private:
        unsigned int rating;
      public:
        RatedPlayer (unsigned int r = 0, const string & fn = "none",
                      const string & ln = "none", bool ht = false);
        RatedPlayer (unsigned int r, const TableTennisPlayer & tp);
        unsigned int Rating() const { return rating;}
        void ResetTable (unsigned int r) {rating = r;}
    };
    
    #endif

tabtenn1.cpp

#include "tabtenn1.h"
    #include <iostream>
    
    TableTennisPlayer::TableTennisPlayer(const string & fn,
      const string & ln, bool ht) : firstname(fn),
          lastname(ln), hasTable(ht) {}
    
    void TableTennisPlayer::Name() const
    {
      std::cout << lastname << ", " << firstname;
    }
    
    RatedPlayer::RatedPlayer(unsigned int r, const string & fn,
          const string & ln, bool ht) : TableTennisPlayer(fn, ln, ht)
    {
      rating = r;
    }
    
    RatedPlayer::RatedPlayer(unsigned int r, const TableTennisPlayer & tp)
      : TableTennisPlayer(tp), rating(r)
      {
      }

usett1.cpp

#include <iostream>
    #include "tabtenn1.h"
    
    int main(void)
    {
      using std::cout;
      using std::endl;
      TableTennisPlayer player1("Tara", "Boomdea", false);
      RatedPlayer rplayer1(1140, "Mallory", "Duck", true);
      rplayer1.Name();
      if (rplayer1.HasTable())
        cout << ": has a table.\n";
      else
        cout << ": hasn't a table.\n";
      player1.Name();
      if (player1.HasTable())
        cout << ": has a table";
      else
        cout << ": hasn't a table.\n";
      cout << "Name: ";
      rplayer1.Name();
      cout << "; Rating: " << rplayer1.Rating() << endl;
      RatedPlayer rplayer2(1212, player1);
      cout << "Name: ";
      rplayer2.Name();
      cout << "; Rating: " << rplayer2.Rating() << endl;
    
      return 0;
    }

其他：

派生类可以用非私有的基类方法

基类指针或引用可以自动转换成指向派生类的对象。 BUT 基类指针或引用依然只能使用基类的函数 而不能调用派生类的自己的函数

不能反过来 也就是说 不能将基类对象的指针或引用赋值给派生类的指针或引用

![20190528184054158.png][]

关于将派生类对象传递给基类对象初始化

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3NvdWx3eWI_size_16_color_FFFFFF_t_70 1][]

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3NvdWx3eWI_size_16_color_FFFFFF_t_70 2][]

也就是说 派生类传递到基类对象中进行初始化  编译器会调用相应的复制构造函数 然后将基类涉及到的形参传递过去。不涉及的就丢给派生类的构造函数去处理。

完结

[2019052818264935.png]: /images/20220126/d1146747df6d47e09be5057d3dd75aae.png
[20190528182655636.png]: /images/20220126/caf4ea46035a4d7e955cbca7939da9a0.png
[20190528182704847.png]: /images/20220126/33af70c4b0a74fa2a8773b92b9a60be6.png
[2019052818271588.png]: /images/20220126/98345b84785a4dfc949a189b32b61594.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3NvdWx3eWI_size_16_color_FFFFFF_t_70]: /images/20220126/8be9c6a35ef54cb49a71d312c49e3530.png
[20190528184054158.png]: /images/20220126/d5ac49f7b02b434789b77319fb1ed9c6.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3NvdWx3eWI_size_16_color_FFFFFF_t_70 1]: /images/20220126/613e7b24d8834eeda06a33dede7c34b2.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3NvdWx3eWI_size_16_color_FFFFFF_t_70 2]: /images/20220126/09dd5b8b8f1441e6a97d3fee0cc3e902.png