c++-纯虚函数和抽象类
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2022-08-02 21:56:54
纯虚函数和抽象类 + C面向接口编程和C多态 函数类型语法基础 函数指针做函数参数(回调函数)思想剖析 函数指针做函数参数两种用法(正向调用、反向调用) + 纯虚函数 抽象类 抽象类基本概念 抽象类在多继承中的应用 面向抽象类编程案例强化 C面向接口编程和C多态 上一个知识的小练习 纯虚函数和多继承 ......
纯虚函数和抽象类
- c面向接口编程和c多态
- 函数类型语法基础
- 函数指针做函数参数(回调函数)思想剖析
- 函数指针做函数参数两种用法(正向调用、反向调用)
- 纯虚函数 抽象类
- 抽象类基本概念
- 抽象类在多继承中的应用
- 面向抽象类编程案例强化
- c面向接口编程和c多态
#define _crt_secure_no_warnings #include <iostream> using namespace std; //图形类 //如果说一个类 拥有一个纯虚函数 //就称这个类是一个抽象类。 //不管这个类中有没有成员属性,只要这个类有纯虚函数,就是一个抽象类, 抽象类就是不能够实例化的。 class shape { public: //求图形面积的方法 //表示图形类声明一个方法getarea(),它是一个纯虚函数,没有函数的实现。 virtual double getarea() = 0; }; //三角形 class tri :public shape { public: tri(int a, int h) { this->a = a; this->h = h; } virtual double getarea() { cout << "三角形求面价" << endl; return 0.5*a*h; } private: int a; int h; }; //正方形: //如果说一个普通类,继承拥有纯虚函数的类,如果说不重写纯虚函数,依然是一个抽象类。 //依然不能被实例化, 如果想实例化, 必须要重写这个父类中所有纯虚函数 class rect : public shape { public: rect(int a) { this->a = a; } virtual double getarea() { cout << "正方形求面积" << endl; return a*a; } private: int a;//正方形边长 }; class circle :public shape { public: circle(int r) { this->r = r; } virtual double getarea() { cout << "圆形求面积" << endl; return 3.14*r * 4; } private: int r; }; //面向抽象类写一个架构函数 void printarea(shape *sp) { sp->getarea(); } //业务层 面向的抽象类编程 int main(void) { //main 中所有使用的变量类型 都是 抽象类shape的类型。 shape *sp1 = new rect(10); //sp1->getarea(); shape *sp2 = new circle(20); //sp2->getarea(); shape *sp3 = new tri(10, 20); //sp3->getarea(); printarea(sp1); printarea(sp2); printarea(sp3); return 0; }
上一个知识的小练习
#define _crt_secure_no_warnings #include <iostream> using namespace std; //大哥的虚衔 class bigbrother { public: //会打人。 virtual void fightpeople() = 0; }; //东方不败 class eastneverlose :public bigbrother { public: virtual void fightpeople() { cout << "使用了葵花宝典区打人" << endl; } }; //无崖子 class wuyazi :public bigbrother { public: virtual void fightpeople() { cout << "使用北冥神功打人" << endl; } }; //boss int main(void) { bigbrother *bigbrother = new wuyazi; //大哥你给我去打人。 bigbrother->fightpeople(); delete bigbrother; return 0; }
纯虚函数和多继承
#define _crt_secure_no_warnings #include <iostream> using namespace std; //接口1 class interface1 { public: virtual void func1(int a, int b) = 0; virtual void func3(int a, int b) = 0; }; //接口2 class interface2 { public: virtual void func2(int a) = 0; }; class child :public interface1, public interface2 { public: virtual void func1(int a, int b) { cout << "func1" << endl; } virtual void func3(int a, int b) { cout << "func3" << endl; } virtual void func2(int a) { cout << "func2 " << endl; } }; int main(void) { interface1 *if1 = new child; if1->func1(10, 20); if1->func3(100, 200); interface2 *if2 = new child; if2->func2(10); return 0; }
电脑组装--小练习
#define _crt_secure_no_warnings #include <iostream> using namespace std; //-------- 抽象层--------- //抽象cpu类 class cpu { public: cpu(); virtual void caculate() = 0; }; //抽象的card类 class card { public: virtual void display() = 0; }; //抽象的内存类 class memory { public: virtual void storage() = 0; }; //架构类 class computer { public: computer(cpu *cpu, card *card, memory *mem) { this->cpu = cpu; this->card = card; this->mem = mem; } void work() { this->cpu->caculate(); this->card->display(); this->mem->storage(); } ~computer() { if (this->cpu != null) { delete this->cpu; } if (this->card != null) { delete this->card; } if (this->mem != null) { delete this->mem; } } private: cpu* cpu; card*card; memory *mem; }; // -------------------------- //-----------实现层---------- //具体的intelcpu class intelcpu :public cpu { public: virtual void caculate() { cout << "intel cpu开始计算了" << endl; } }; class intelcard :public card { public: virtual void display() { cout << "intel card开始显示了" << endl; } }; class intelmem :public memory { public: virtual void storage() { cout << "intel mem开始存储了" << endl; } }; class nvidiacard :public card { public: virtual void display() { cout << "nvidia 显卡开始显示了" << endl; } }; class kingstonmem :public memory { public: virtual void storage() { cout << "kingstonmem 开始存储了" << endl; } }; //-------------------------- //--------业务层------------------- int main(void) { //1 组装第一台intel系列的电脑 #if 0 cpu *intelcpu = new intelcpu; card *intelcard = new intelcard; memory *intelmem = new intelmem; computer *com1 = new computer(intelcpu, intelcard, intelmem); com1->work(); card *ncard = new nvidiacard; memory* kmem = new kingstonmem; computer *com2 = new computer(intelcpu, ncard, kmem); com2->work(); delete intelcpu; #endif computer *com1 = new computer(new intelcpu, new intelcard, new intelmem); com1->work(); delete com1; return 0; }