const（每个对象中的常量）, static const（类的编译时常量）

 1 #include <iostream>
 2 using namespace std;
 3 
 4 class Values
 5 {
 6 private:
 7     
 8     //类里的
 9     const int cSize; //常量成员的初始化，必须在构造函数中进行，每个对象都有，只是成员常量数据在初始化就不能改变
10     
11     
12     //禁止在类内对"非const的静态成员"进行初始化
13     //static int sFloat = 100; //Values.cpp:8:24: error: ISO C++ forbids in-class initialization of non-const static member ‘Values::sFloat’
14     static float sFloat; //类的静态成员，所以对象共享同一块内存单元
15     static int sInts[];
16     
17     
18     
19     static const float scFloat; //类的静态常量成员在类中初始化
20     static const int scInts[];
21     
22     int size;
23     
24 public:
25     Values(const int cSize, int sz) : cSize(cSize), size(sz) {}
26     
27     void print() const;
28     
29     static void printStatic();
30 };
31 
32 
33 //类的普通private成员
34 //int Values::size = 100; //error C2350: ‘Values::size‘ is not a static member
35 
36 //类的静态数据成员初始化
37 float Values::sFloat = 1.1; 
38 int Values::sInts[] = {1, 2, 3};
39 
40 //类静态常量数据成员初始化
41 const float Values::scFloat = 100.01;
42 const int Values::scInts[] = {11, 22, 33};
43 
44 //定义一个全局变量size
45 int size = 7;
46 
47 
　　//成员函数中，可以访问到类的静态成员
48 void Values::print() const
49 {
50     cout<<"::size = "<<size<<endl;
51     cout<<"Values::cSize = "<<cSize<<endl;
52     cout<<"Values::size = "<<size<<endl;
53     cout<<"Values::sFloat = "<<sFloat<<endl;
54     cout<<"Values::scFloat = "<<scFloat<<endl;
55 }
56 
57 
　　//在静态成员函数中，只能访问到类的静态成员
58 void Values::printStatic()
59 {
60     cout<<"printStatic(), Values::scFloat = "<<scFloat<<endl;
61     cout<<"printStatic(), Values::scInts[] = {"<< scInts[0] <<", " <<scInts[1] << ", " << scInts[2] <<"}"<<endl;
62     
63     cout<<"printStatic(), Values::sFloat = "<<sFloat<<endl;
64     cout<<"printStatic(), Values::sInts[] = {"<< sInts[0] <<", " <<sInts[1] << ", " << sInts[2] <<"}"<<endl;
65 }
66 
67 
68 int main()
69 {
70     Values v(1, 3);
71     
72     v.print();
73     
74     Values::printStatic();
75     
76     return 0;
77 }

输出：

::size = 3
Values::cSize = 1
Values::size = 3
Values::sFloat = 1.1
Values::scFloat = 100.01

printStatic(), Values::scFloat = 100.01
printStatic(), Values::scInts[] = {11, 22, 33}
printStatic(), Values::sFloat = 1.1
printStatic(), Values::sInts[] = {1, 2, 3}