多态继承虚函数与异常 

  1 /* 异常的继承与虚函数 */
  2 
  3 #include<iostream>
  4 
  5 using namespace std;
  6 
  7 class print3dbox
  8 {
  9 public:
 10     print3dbox(int num)
 11     {
 12         if (num==0)
 13         {
 14             throw zero(1);
 15         }
 16         else if (num<10 && num>0)
 17         {
 18             throw small();
 19         }
 20         else if (num>1000)
 21         {
 22             throw big();
 23         }
 24     }
 25 
 26     class small
 27     {
 28 
 29     };
 30 
 31     class big
 32     {
 33 
 34     };
 35 
 36     class zero:public small// 异常类可以派生
 37     {
 38     public:
 39         int errorcode;
 40         zero(int codeid):errorcode(codeid)
 41         {
 42         
 43         }
 44     };
 45 
 46 private:
 47     int x;
 48 };
 49 
 50 void main()
 51 {
 52     try
 53     {
 54         print3dbox box(1);
 55     }
 56     catch (print3dbox::zero e)
 57     {
 58         cout << typeid(e).name() << endl;        
 59     }
 60     catch (print3dbox::small e)
 61     {
 62         cout << typeid(e).name() << endl;        
 63     }
 64     catch (print3dbox::big e)
 65     {
 66         cout << typeid(e).name() << endl;        
 67     }
 68 }
 69 
 70 //-------------------------------------------------------------------------------
 71 
 72 
 73 /* 异常的多态与虚函数 */
 74 
 75 #include<iostream>
 76 
 77 using namespace std;
 78 
 79 class print3dbox
 80 {
 81 public:
 82     print3dbox(int num)
 83     {
 84         error *p = nullptr;// 空指针
 85         if (num==0)
 86         {
 87             p = new zeroerro;
 88             throw p;
 89         }
 90         else if (num<10 && num>0)
 91         {
 92             p = new smallerror;
 93             throw p;
 94         }
 95         else if (num>1000)
 96         {
 97             p = new bigerror;
 98             throw p;
 99         }
100     }
101 
102     class error
103     {
104     public:
105         // virtual void showerror() = 0;// 直接设置成纯虚函数也可以
106         virtual void showerror()
107         {
108             cout << "virtual void showerror()" << endl;
109         }
110     };
111 
112     class bigerror:public error
113     {
114     public:
115         void showerror()
116         {
117             cout << "class bigerror void showerror()" << endl;
118         }
119     };
120 
121     class smallerror : public error
122     {
123     public:
124         void showerror()
125         {
126             cout << "class smallerror void showerror()" << endl;
127         }
128     };
129 
130     class zeroerro : public error
131     {
132     public:
133         void showerror()
134         {
135             cout << "class zeroerro void showerror()" << endl;
136         }
137     };
138 
139 private:
140     int x;
141 };
142 
143 void main()
144 {
145     try
146     {
147         print3dmax box(0);
148     }
149     catch (print3dmax::error *p)
150     {
151         p->showerror();
152     }
153     
154     cin.get();
155 }

 

posted on 2015-06-16 14:21  Dragon-wuxl  阅读(99)  评论(0)    收藏  举报

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