//ts5.java   用 List做 Stack --- by tsaiwn@csie.nctu.edu.tw 
import java.util.*;
class MyStack extends ArrayList{
 /////////////////// 原則:  Data 藏起來, functions 公開
  public MyStack( ) { super( ); }  // 
  synchronized public void push(Object o) {
     add(o);
  }
  synchronized public Object peek( ) { return get(size( )-1 ); }  // C++ 叫做 top( )
  synchronized public Object pop( ) { 
      int last = size( ) - 1;
      Object tmp = get( last );
      remove( last );
      return tmp;
  }
  public boolean empty( ) { return isEmpty( ); }
  public boolean full( ) { return false; }
} // MyStack
// Note that the Stack in Library is made of Vector
class ts5 {
   static double x[ ] = {1,21,23,24,5,8,22,2,3,4,25,28};
   public static void testaa( ) {
      MyStack ss = new MyStack( );
      for(double y:x) {
         System.out.print(y+"  ");
         ss.push(y);     // JDK 1.5 後會 autoBoxing
      } // for
      System.out.println("\n=== now check stack ...");
      while( !ss.empty( ) ) {
         System.out.print(""+ ss.pop( ) + " ");
      }
      System.out.println();
   } 
////// use Library Stack  // 注意 testaa( ) 與 testbb( ) 完全相同!
   public static void testbb( ) {
      Stack ss = new Stack( );    // 除了這裡用程式庫的 Stack
      for(double y:x) {
         System.out.print(y+"  ");
         ss.push(y);   // JDK1.4.x 以前不可以!
      } // for
      System.out.println("\n=== now check stack ...");
      while( !ss.empty( ) ) {
         System.out.print(""+ ss.pop( ) + " ");
      }
      System.out.println();
   } 
   public static void main( String xx[]) {
      testaa( );
      println("===Now using Library Stack...");
      testbb( );
      println("===");
      Arrays.sort(x);
      for(double y:x) System.out.print(y+" "); println("");
      Double dx[ ] = new Double[x.length];
      for(int i=0; i < x.length; ++i) 
          Arrays.fill(dx, i, i+1, new Double(x[i]));
      println("====== dx.length=" + dx.length);
       for(Double y:dx) System.out.print(y+" "); println("");
      GG g = new GG( );
      Arrays.sort(dx, g);
       for(Double y:dx) System.out.print(y+" "); println("");
   } // main
 static void println(String s){System.out.println(s);}
} // class ts5
class GG implements Comparator {
   public int compare(Object x, Object y) {
      if(x==null) return 1; if(y==null)return -1;
      Double xx = (Double)x; Double yy=(Double)y;
      double ans = yy - xx;   // auto unboxing
      if(ans==0) return 0;
      return ans>0? 1: -1;
   }
}