D语言类模板

import std.stdio; 
import std.string; 

class Stack(T) { 
   private: 
      T[] elements;  
   public:  
      void push(T element) { 
         elements ~= element; 
      }
      void pop() { 
         --elements.length; 
      } 
      T top() const @property { 
         return elements[$ - 1]; 
      }
      size_t length() const @property { 
         return elements.length; 
      } 
}

void main() { 
   auto stack = new Stack!string;

   stack.push("Test1"); 
   stack.push("Test2");  

   writeln(stack.top); 
   writeln(stack.length); 

   stack.pop; 
   writeln(stack.top); 
   writeln(stack.length); 
}