// Main program (for testing)
// Output should be
// value on stack at position 0 is 1
// value on stack at position 1 is 2
// popped off value 2
// value on stack at position 0 is 1
// value on stack at position 0 is 0
// value on stack at position 1 is 1
// value on stack at position 2 is 2
// value on stack at position 3 is 3
// value on stack at position 4 is 4
// value on stack at position 5 is 5
// value on stack at position 6 is 6
// value on stack at position 7 is 7
// value on stack at position 8 is 8
// value on stack at position 9 is 9
// value on stack at position 10 is 10
// value on stack at position 11 is 11
// value on stack at position 12 is 12
// value on stack at position 13 is 13
// value on stack at position 14 is 14
// value on stack at position 15 is 15
// value on stack at position 16 is 16
// value on stack at position 17 is 17
// value on stack at position 18 is 18
// value on stack at position 19 is 19
public static void main( String args[] ) {
    IntStack s = new IntStack();
    s.push(1);
    s.push(2);
    for (int i= 0; i < s.size(); i++) {
	System.out.println( "value on stack at position " + i + " is " + s.elementAt(i) );
    }
    System.out.println( "popped off value " + s.pop() );
    for (int i= 0; i < s.size(); i++) {
	System.out.println( "value on stack at position " + i + " is " + s.elementAt(i) );
    }

    s = new IntStack();
    for (int i = 0; i < 20; i++) {
	s.push( i );
    }
    for (int i= 0; i < s.size(); i++) {
	System.out.println( "value on stack at position " + i + " is " + s.elementAt(i) );
    }
} // end main