136.异常的多态,父类对象,传递子类的引用或指针(地址) 

 1 #include <iostream>
 2 using namespace std;
 3 
 4 //纯虚类
 5 class error
 6 {
 7 public:
 8     //纯虚函数
 9     virtual void showerror() = 0;
10 };
11 
12 class big :public error
13 {
14 public:
15     void showerror()
16     {
17         cout << "big error" << endl;
18     }
19     
20 };
21 
22 class small :public error
23 {
24 public:
25     void showerror()
26     {
27         cout << "small error" << endl;
28     }
29 
30 };
31 
32 class zero :public error
33 {
34 public:
35     void showerror()
36     {
37         cout << "zero error" << endl;
38     }
39 
40 };
41 
42 //抛出一个引用对象
43 class print3d
44 {
45 public:
46     print3d(double size)
47     {
48         if (size == 0)
49         {
50             throw &zero();
51         }
52         else if (size > 1000)
53         {
54             throw &big();
55         }
56         else if (size < 1)
57         {
58             throw &small();
59         }
60     }
61 };
62 
63 void main()
64 {
65     try
66     {
67         print3d dg(0);
68     }
69     catch (error *p)
70     {
71         p->showerror();
72     }
73     cin.get();
74 }

 

posted @ 2018-04-01 12:38  喵小喵~  阅读(165)  评论(0)    收藏  举报