C++里的继承和多态(中)——分析单继承、多继承、菱形继承(不含虚函数)
继承
1、单继承
classBase{public:Base(){cout<<"Base()"<<this<<endl;}voidFunTest1(){cout<<"Base::FunTest1()"<<endl;}voidFunTest2(){cout<<"Base::FunTest2()"<<endl;}~Base(){cout<<"~Base()"<<endl;}int_data1;};classDerive:publicBase{public:voidFunTest3(){cout<<"Derive::FunTest3()"<<endl;}int_data2;};intmain(){Baseb;b.FunTest1();b.FunTest2();b._data1=0x04;Derived;d.FunTest1();d.FunTest2();d.FunTest3();d._data1=0x01;d._data2=0x02;return0;}
——b对象和d对象的对象模型
main 函数的反汇编
派生类的构造函数:
程序运行结果:
构造函数:
基类构造函数:Base( )884 ->派生类构造函数: Base( )874 ->Derive( )874
析构函数:
派生类的析构函数:~Derive( )874 -> ~Base( )874->基类的析构函数:~Base( )884
2、多继承
classBase{public:Base(){cout<<"Base()"<<this<<endl;}voidFunTest1(){cout<<"Base::FunTest1()"<<endl;}voidFunTest2(){cout<<"Base::FunTest2()"<<endl;}~Base(){cout<<"~Base()"<<endl;}int_data1;};classBase1{public:Base1(){cout<<"Base1()"<<endl;}voidFunTest3(){cout<<"Base::FunTest3()"<<endl;}voidFunTest4(){cout<<"Base::FunTest4()"<<endl;}int_data3;};classDerive:publicBase,publicBase1{public:Derive(){cout<<"Derive()"<<this<<endl;}voidFunTest5(){cout<<"Derive:FunTest5()"<<endl;}~Derive(){cout<<"~Derive()"<<endl;}int_data2;};intmain(){Baseb;b.FunTest1();b.FunTest2();b._data1=0x04;Base1b1;b1.FunTest3();b1.FunTest4();b1._data3=0x05;Derived;d.FunTest1();d.FunTest2();d.FunTest3();d.FunTest4();d.FunTest5();d._data1=0x01;d._data2=0x02;d._data3=0x03;return0;}
main函数的反汇编:
派生类的构造函数:
先调用Base的构造函数,再调用Base1的构造函数
析构函数的调用:
先是派生类的析构函数,再试Base1的析构函数,最后是Base的析构函数
在派生类的析构函数中又会调用基类的析构函数:
在派生类的析构函数中,也是先调用Base1的析构函数,再调用Base的析构函数。与构造函数的顺序正好相反
程序运行的结果:
构造函数:
j基类的构造函数:Base( )D9c -> Base1( )D90 -> 派生类中的构造函数:Base( )D7c -> Base1 ( )D80 -> Derive( )D7c
析构函数:
派生类中的析构函数:~Derive( )D7c -> ~Base1( )D80 -> ~Base( )D7c ->基类的析构函数:~Base1( )D90 -> ~Base( )D9C
3、菱形继承
classBase{public:Base(){cout<<"Base()"<<this<<endl;}voidFunTest1(){cout<<"Base::FunTest1()"<<endl;}~Base(){cout<<"~Base()"<<endl;}};classDerive:publicBase{public:Derive(){cout<<"Derive()"<<this<<endl;}voidFunTest2(){cout<<"Derive:FunTest2()"<<endl;}~Derive(){cout<<"~Derive()"<<endl;}};classDerive1:publicBase{public:Derive1(){cout<<"Derive1()"<<this<<endl;}voidFunTest3(){cout<<"Derive:FunTest4()"<<endl;}~Derive1(){cout<<"~Derive1()"<<endl;}};classDerive2:publicDerive,publicDerive1{public:Derive2(){cout<<"Derive2()"<<endl;}voidFunTest4(){cout<<"Derive:FunTest4()"<<endl;}};intmain(){Baseb;b.FunTest1();Derived;d.FunTest1();d.FunTest2();Derive1d1;d1.FunTest1();d1.FunTest3();Derive2d2;//d2.FunTest1();会出现二义性d2.Derive::FunTest1();d2.Derive1::FunTest1();d2.FunTest2();d2.FunTest3();d2.FunTest4();return0;}
对象模型:
Derive和Derive1中都含有了Base,会产生二义性和数据冗余。
main函数的反汇编:
派生类的构造函数:
在派生类的构造函数中,都先调用的基类的构造函数。
Derive()
Derive1()
Derive2()
析构函数的调用:
析构函数的顺序和构造函数的顺序正好相反。
~Derive2( )->~Derive1( )->~Derive( )->~Base( ),
派生类中析构函数的调用:
在~Derive2(),先是自己的析构函数,再调用了~Derive1(),再调用了~Derive(),
在~Derive1( )中先是自己的析构函数,又调用了~Base()
在~Derive( )中先是自己的析构函数,又调用了~Base()
程序运行结果:
构造函数:
Base( )B8F ->
Derive的构造函数:Base( )B83 -> Derive( )B83->
Derive1的构造函数:Base( )B77 -> Derive1( )B77->
Derive2的构造函数:Base( )B6B -> Derive( )B6B ->Base( )B6C -> Derive1( )B6C ->Derive2( )B6B
析构函数:
~Derive2( )B6B -> ~Derive1( )B6C ->~Base( )B6C -> ~Derive( )B6B -> ~Base( )B6B
~Derive1( )B77 -> ~Base( )B77 -> ~Derive( )B83 -> ~Base( )B83
~Base( )B8F
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