FilesExpand file tree

 master

/

Stack.java

Copy path

Blame

More file actions

Blame

More file actions

Latest commit

 

History

History

History

59 lines (50 loc) · 1.6 KB

 master

/

Stack.java

Copy path

Top

File metadata and controls

• Code
• Blame

59 lines (50 loc) · 1.6 KB

Raw

Copy raw file

Download raw file

Open symbols panel

Edit and raw actions

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

19

20

21

22

23

24

25

26

27

28

29

30

31

32

33

34

35

36

37

38

39

40

41

42

43

44

45

46

47

48

49

50

51

52

53

54

55

56

57

58

59

// A cloneable version of Stack - Pages 56-57

import java.util.Arrays;

public class Stack implements Cloneable {

private Object[] elements;

private int size = 0;

private static final int DEFAULT_INITIAL_CAPACITY = 16;

public Stack() {

this.elements = new Object[DEFAULT_INITIAL_CAPACITY];

}

public void push(Object e) {

ensureCapacity();

elements[size++] = e;

}

public Object pop() {

if (size == 0)

throw new EmptyStackException();

Object result = elements[--size];

elements[size] = null; // Eliminate obsolete reference

return result;

}

public boolean isEmpty() {

return size == 0;

}

@Override public Stack clone() {

try {

Stack result = (Stack) super.clone();

result.elements = elements.clone();

return result;

} catch (CloneNotSupportedException e) {

throw new AssertionError();

}

}

// Ensure space for at least one more element.

private void ensureCapacity() {

if (elements.length == size)

elements = Arrays.copyOf(elements, 2 * size + 1);

}

// To see that clone works, call with several command line arguments

public static void main(String[] args) {

Stack stack = new Stack();

for (String arg : args)

stack.push(arg);

Stack copy = stack.clone();

while (!stack.isEmpty())

System.out.print(stack.pop() + " ");

System.out.println();

while (!copy.isEmpty())

System.out.print(copy.pop() + " ");

}

}