C++第四章课后习题4-12

定义一个datatype类，能处理包含字符型，整形，浮点型3种类型的数据，给出其构造函数。

 1 #include <iostream>
 2 using namespace std;
 3 
 4 class DataType{
 5     private:
 6         char a;
 7         int n;
 8         float x;
 9 enum {
10     character,
11     integer,
12     floating,
13 } vartype;
14     public:
15         DataType(char a)
16         {
17             vartype=character;
18             this->a=a;
19         }
20         DataType(int n)
21         {
22             vartype=integer;
23             this->n=n;
24         }
25         DataType(float x)
26         {
27             vartype=floating;
28             this->x=x;
29         }
30         void print()
31         {
32             switch(vartype){
33                 case character:
34                     cout<<"zifu"<<a<<endl;
35                     break;
36                 case integer:
37                     cout<<"zhengshu"<<n<<endl;
38                     break;
39                 case floating:
40                     cout<<"fudiashu"<<x<<endl;
41                     break;
42             }
43         }
44 }; 
45 int main()
46 {
47     DataType a('c'),b(1),c(1.44F);
48     a.print();
49     b.print();
50     c.print();
51 }