c ++ - Polymorphic small case

Polymorphic small case

• C oriented programming interface and polymorphism C
  • Syntax basis function type
  • Function pointer of function parameters (callback) Ideology of the
  • Function pointer function parameters do two uses (call forward, reverse call)
• Pure virtual function abstract class
  • The basic concept of abstract classes
  • Application abstract class multiple inheritance in
  • Oriented programming to abstract classes Case strengthen
• Oriented programming to abstract classes Case strengthen
• Application abstract class multiple inheritance in
• The basic concept of abstract classes

Polymorphic Graphics Case

#define _CRT_SECURE_NO_WARNINGS
#include <iostream>


using namespace std;


//抽象的图形类
class Shape
{
public:
    //打印出图形的基本你属性
    virtual void show() = 0;
    //得到图形的面积
    virtual double getArea() = 0;

    virtual ~Shape() {

    }
};

//圆类
class Circle :public Shape
{
public:
    Circle(double r) {
        this->r = r;
    }

    //打印出图形的基本你属性
    virtual void show()  {
        cout << "圆的半径是 " << r << endl;
    }
    //得到图形的面积
    virtual double getArea()  {
        cout << "获取圆的面积" << endl;
        return this->r*this->r *3.14;
    }
    ~Circle() {
        cout << "圆的析构函数。。" << endl;
    }
private:
    double r;
};

class Square :public Shape
{
public:
    Square(double a) {
        this->a = a;
    }

    //打印出图形的基本你属性
    virtual void show() {
        cout << "正方形的边长是" << this->a << endl;
    }
    //得到图形的面积
    virtual double getArea() {
        cout << "得到正方形的面积" << endl;
        return a*a;
    }


    ~Square() {
        cout << "正方形的析构函数" << endl;
    }
private:
    double a;
};



int main(void)
{
    Shape *array[2] = { 0 };

    for (int i = 0; i < 2; i++) {
        //生成一个圆
        if (i == 0) {
            double r;
            cout << "请输入圆的半径" << endl;
            cin >> r;
            array[i] = new Circle(r);
        }
        //生成一个正方形
        else {
            double a;
            cout << "请输入正方形的边长" << endl;
            cin >> a;
            array[i] = new Square(a);
        }
    }


    //遍历这个array数组
    for (int i = 0; i < 2; i++) {
        array[i]->show();
        cout << array[i]->getArea() << endl;

        delete array[i];
    }

    return 0;
}

Polymorphic cases - Programmer salary

#define _CRT_SECURE_NO_WARNINGS
#include <iostream>


using namespace std;

class Programmer
{
public:
    Programmer(double salary)
    {
        this->salary = salary;
    }
    virtual void printMoney() = 0;
    virtual ~Programmer() {

    }

protected:
    double salary;
};


class Junior_programmer :public Programmer
{
public:
    Junior_programmer(double salary) :Programmer(salary) {

    }
    virtual void printMoney(){
        cout << "初级程序员的工资是" << this->salary << endl;
    }
};

class Mid_programmer :public Programmer
{
public:
    Mid_programmer(double salary) :Programmer(salary) {

    }
    virtual void printMoney(){
        cout << "中级程序员的工资是" << this->salary << endl;
    }
};

class Adv_programmer :public Programmer
{
public:
    Adv_programmer(double salary) :Programmer(salary) {

    }
    virtual void printMoney(){
        cout << "高级程序员的工资是" << this->salary << endl;
    }
};





int main(void)
{

    Programmer * pro1 = new Junior_programmer(12000);

    pro1->printMoney();

    delete pro1;


    Programmer * pro2 = new Mid_programmer(15000);
    pro2->printMoney();
    delete pro2;

    Programmer *pro3 = new Adv_programmer(30000);
    pro3->printMoney();
    delete pro3;


    
    return 0;
}

And array type array pointer

#define _CRT_SECURE_NO_WARNINGS
#include <iostream>


using namespace std;

//方法一： 直接定义一个数组类型
typedef int(ARRAY_INT_10)[10];


//方法二：
typedef int(*ARRAY_INT_10_P)[10];

int main(void)
{
    int array[10]; //array 应该是一个指向int类型指针。

    //方法一：
    //ARRAY_INT_10 *array_10_p = &array; //? *array_10_p === array

    //方法二：
    ARRAY_INT_10_P array_10_p = &array;

    for (int i = 0; i < 10; i++) {
        (*array_10_p)[i] = i + 10;
    }

    for (int i = 0; i < 10; i++) {
        cout << array[i] << endl;
    }

    //方法三：
    int(*p)[10] = &array;

    cout << "------" << endl;
    for (int i = 0; i < 10; i++) {
        cout << (*p)[i] << endl;
    }

    return 0;
}

Function pointer

#define _CRT_SECURE_NO_WARNINGS
#include <iostream>


using namespace std;

int func(int a, int b)
{
    cout << " 1999 年写的 func" << endl;

    return 0;
}

int func2(int a, int b)
{
    cout << "1999 写的 func2" << endl;
    return 0;
}

int func3(int a, int b) 
{
    cout << "1999年 写的 func3 " << endl;
    return 0;
}

//2018想添加一个新的子业务
int new_func4(int a, int b)
{
    cout << "2018 新写的子业务" << endl;
    cout << "a = " << a << ", b = " << b << endl;
    return 0;
}

//方法一：  函数的返回值， 函数的参数列表（形参的个数，类型，顺序）
//定义一个函数类型。

typedef int(FUNC)(int, int);

//方法二：   定义一个函数指针
typedef int(*FUNC_P)(int, int);


//定义一个统一的接口 将他们全部调用起来。

void my_funtion(int(*fp)(int, int), int a, int b)
{
    cout << "1999年实现这个架构业务" << endl;
    cout << "固定业务1" << endl;
    cout << "固定业务2" << endl;

    fp(a, b);//可变的业务

    cout << "固定业务3" << endl;

}

int main(void)
{
#if 0
    //方法一：
    FUNC *fp = NULL;

    fp = func;
    fp(10, 20);

    FUNC_P fp2 = NULL;

    fp2 = func;

    fp2(100, 200);

    //方法三：
    int(*fp3)(int, int)   = NULL;
    fp3 = func;
    fp3(1000, 3000);
#endif
    my_funtion(func, 10, 20);
    my_funtion(func2, 100, 200);
    my_funtion(func3, 1000, 2000);

    my_funtion(new_func4, 2000, 3000);
    
    return 0;
}

Good ideas

#define _CRT_SECURE_NO_WARNINGS
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <iostream>
#include <fstream>


using namespace std;
//-------------抽象层------------
//定义拆开锦囊方法的类型。
typedef void(TIPS)(void);

//定义锦囊
struct tip
{
    char from[64]; //谁写的
    char to[64];//写给谁的。
    //锦囊的内容
    TIPS *tp;//相当于抽象类的 纯虚函数.
};

//需要一个打开锦囊的架构函数
void open_tips(struct tip *tip_p)
{
    cout << "打开了锦囊" << endl;
    cout << "此锦囊是由" << tip_p->from << "写给 " << tip_p->to << "的。" << endl;
    cout << "内容是" << endl;
    tip_p->tp(); //此时就发生了多态现象。
}

//提供一个创建一个锦囊的方法
struct tip* create_tip(char*from, char *to, TIPS*tp)
{
    struct tip *temp = (struct tip*)malloc(sizeof(struct tip));
    if (temp == NULL) {
        return NULL;
    }
    strcpy(temp->from, from);
    strcpy(temp->to, to);
    //给一个回调函数赋值， 一般称 注册回调函数
    temp->tp = tp;

    return temp;
}

//提供一个销毁锦囊的方法
void destory_tip(struct tip *tp)
{
    if (tp != NULL) {
        free(tp);
        tp = NULL;
    }
}


// ------------- 实现层------------
//诸葛亮写了3个锦囊
void tip1_func(void)
{
    cout << "一到东吴就拜会乔国老" << endl;
}

void tip2_func(void)
{
    cout << "如果主公乐不思蜀，就谎称曹贼来袭。赶紧回来 " << endl;
}

void tip3_func(void)
{
    cout << "如果被孙权追杀，向孙尚香求救" << endl;
}

void tip4_func(void)
{
    cout << "如果求救孙尚香都不灵，  你们去死了， 我是蜀国老大了" << endl;
}


//---------------  业务层-----------------
int main(void)
{
    //创建出3个锦囊
    struct tip *tip1 = create_tip("孔明", "赵云", tip1_func);
    struct tip *tip2 = create_tip("孔明", "赵云", tip2_func);
    struct tip *tip3 = create_tip("孔明", "赵云", tip3_func);
    struct tip *tip4 = create_tip("庞统", "赵云", tip4_func);

    //由赵云进行拆锦囊。
    cout << "刚刚来到东吴， 赵云打开第一个锦囊" << endl;
    open_tips(tip1);
    cout << "-----------" << endl;

    cout << "刘备乐不思蜀， 赵云打开第二个锦囊" << endl;
    open_tips(tip2);
    cout << "-----------" << endl;

    cout << "孙权大军追杀，赵云打开第三个锦囊" << endl;
    open_tips(tip3);
    cout << "-----------" << endl;

    cout << "赵云发现，实在是杀不动了， 打开了第四个锦囊" << endl;
    open_tips(tip4);

    destory_tip(tip1);
    destory_tip(tip2);
    destory_tip(tip3);
    destory_tip(tip4);
    
    return 0;
}