104.virtual虚函数多态与异构数据结构 

  1 #include "mainwindow.h"
  2 #include <QApplication>
  3 #include <list>
  4 #include <QPushButton>
  5 #include<QLabel>
  6 #include<QLineEdit>
  7 
  8 using namespace std;
  9 
 10 //异构数据结构,每个数组元素都是基类指针
 11 //异构链表,每一个结点都是基类的指针,指向了派生类
 12 //基类指针基于多态与虚函数调用派生类的方法
 13 
 14 class object
 15 {
 16 public:
 17     virtual void showit()
 18     {
 19 
 20     }
 21 };
 22 
 23 class mywindow:public object
 24 {
 25 public:
 26     MainWindow *p;
 27 
 28     mywindow()
 29     {
 30         p = new MainWindow;
 31     }
 32 
 33     void showit()
 34     {
 35         p->show();
 36      }
 37 };
 38 
 39 class mylabel:public object
 40 {
 41 public:
 42     QLabel *p;
 43     mylabel()
 44     {
 45         p=new QLabel;
 46     }
 47     void showit()
 48     {
 49         p->show();
 50     }
 51 };
 52 
 53 class myedit:public object
 54 {
 55 public:
 56     QLineEdit *p;
 57     myedit()
 58     {
 59         p=new QLineEdit;
 60     }
 61     void showit()
 62     {
 63         p->show();
 64     }
 65 };
 66 
 67 class mybutton:public object
 68 {
 69   public:
 70     QPushButton *p;
 71     mybutton()
 72     {
 73         p = new QPushButton;
 74     }
 75 
 76     void showit()
 77     {
 78         p->show();
 79     }
 80 };
 81 
 82 int main(int argc, char *argv[])
 83 {
 84     QApplication a(argc, argv);
 85 
 86     list<object *>mylist;
 87 
 88     object *p = new mywindow;
 89     mylist.push_back(p);
 90 
 91     p = new mylabel;
 92     mylist.push_back(p);
 93 
 94     p = new mybutton;
 95     mylist.push_back(p);
 96 
 97     p = new mybutton;
 98     mylist.push_back(p);
 99 
100     for(auto it:mylist)
101     {
102         (*it).showit();
103     }
104     return a.exec();
105 }

 

posted @ 2018-03-19 18:56  喵小喵~  阅读(221)  评论(0)    收藏  举报