C++支持类的嵌套，其语法比较简单。代码是最好的说明。

1 #include 
     
       2 using namespace std; 3  4 class Outter{ 5     public: 6         int a; 7         static int s; 8         //nested class and enclosing class are independent. 9         class Inner{ 10             public:11             int b;12             //nested class can access static members of enclosing class13             int foo(){ return b + s;}14             int bar();15         };16 };17 18 int Outter::s = 1;19 //define a nested class member outside of the class declaration.20 int Outter::Inner::bar(){21     return 0xdeadbeef;22 }23 24 int main(){25     Outter o;26     o.a = 0;27     //if nested class is specified as public, then everyone can use the nested class.28     //if nested class is specified as protected, then only the enclosing class,29     //friend of the enclosing class and derived class of the enclosing class can access the nested class.30     //if the nested class is specified as private, then only the enclosing class31     //and friend of the enclosing class can access the nested class.32     Outter::Inner i;33     i.b = 1;34     cout<
      
       <