1   // Fig. 16.16: StackTest.java
 2   // Program to test java.util.Stack.
 3   import java.util.Stack;              
 4   import java.util.EmptyStackException;
 5
 6   public class StackTest
 7   {
 8      public StackTest()
 9      {
10         Stack< Number > stack = new Stack< Number >();
11
12         // create numbers to store in the stack
13         Long longNumber = 12L;
14         Integer intNumber = 34567;
15         Float floatNumber = 1.0F;
16         Double doubleNumber = 1234.5678;
17
18         // use push method
19         stack.push( longNumber ); // push a long
20         printStack( stack );
21         stack.push( intNumber ); // push an int
22         printStack( stack );
23         stack.push( floatNumber ); // push a float
24         printStack( stack );
25         stack.push( doubleNumber ); // push a double
26         printStack( stack );
27
28         // remove items from stack
29         try
30         {
31            Number removedObject = null;
32
33            // pop elements from stack
34            while ( true )
35            {
36               removedObject = stack.pop(); // use pop method
37               System.out.printf( "%s popped\n", removedObject );
38               printStack( stack );
39            } // end while
40         } // end try
41         catch ( EmptyStackException emptyStackException )
42         {
43            emptyStackException.printStackTrace();
44         } // end catch
45      } // end StackTest constructor
46
47      private void printStack( Stack< Number > stack )
48      {
49         if ( stack.isEmpty() )
50            System.out.print( "stack is empty\n\n" ); // the stack is empty
51         else // stack is not empty
52         {
53            System.out.print( "stack contains: " );
54
55            // iterate through the elements
56            for ( Number number : stack )
57               System.out.printf( "%s ", number );
58
59            System.out.print( "(top) \n\n" ); // indicates top of the stack
60         } // end else
61      } // end method printStack
62
63      public static void main( String args[] )
64      {
65         new StackTest();
66      } // end main
67   } // end class StackTest

					  

stack contains: 12 (top)

stack contains: 12 34567 (top)

stack contains: 12 34567 1.0 (top)

stack contains: 12 34567 1.0 1234.5678 (top)

1234.5678 popped
stack contains: 12 34567 1.0 (top)

1.0 popped
stack contains: 12 34567 (top)

34567 popped
stack contains: 12 (top)

12 popped
stack is empty

java.util.EmptyStackException
        at java.util.Stack.peek(Unknown Source)
        at java.util.Stack.pop(Unknown Source)
        at StackTest.<init>(StackTest.java:36)
        at StackTest.main(StackTest.java:65)