D语言数据封装

import std.stdio;

class Adder { 
   public: 
      // constructor 
      this(int i = 0) { 
         total = i; 
      } 

      // interface to outside world 
      void addNum(int number) { 
         total += number; 
      } 

      // interface to outside world 
      int getTotal() { 
         return total; 
      }; 

   private: 
      // hidden data from outside world 
      int total; 
}

void main( ) { 
   Adder a = new Adder(); 

   a.addNum(10); 
   a.addNum(20); 
   a.addNum(30);  
   writeln("Total ",a.getTotal()); 
}