我的 C++ style

 int g_tennis;    // not use as possible

 int make_world() {
     int size = ;

     return size;
 }

 const int NUMBER = ;

 enum Color {
     RED,
     GREEN
 };

 typedef int Dog;

 class MyClass {
     public:
         MyClass(int s, int num_entries = )
             : size(s), num_entries_(num_entries), length_() {
                 int book = NUMBER;
                 book = ;
             }

         int size;

         // same as data member
         int num_entries() const {
             return num_entries_;
         }

         void set_num_entries(int num_entries) {
             num_entries_ = num_entries;
         }

         // private and protected name end with underline
     private:
         int num_entries_;

         void foo_(double world) {
             double *pworld = &world;
             pworld = nullptr;
         }

     protected:
         int length_;
 };

 int main() {

     return ;
 }