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Interface structure.Stack

public interface Stack
extends Linear
An interface describing a Last-In, First-Out structure. Stacks are typically used to store the state of a recursively solved problem.

Method Index

o add(Object)
Add an element from the top of the stack.
o empty()
Returns true iff the stack is empty.
o peek()
Fetch a reference to the top element of the stack.
o pop()
Remove an element from the top of the stack.
o push(Object)
Add an element to top of stack.
o remove()
Remove an element from the top of the stack.

Methods

o add 
public abstract void add(Object item)
Add an element from the top of the stack.

Postcondition:
item is added to stack will be popped next if no intervening add

Parameters:
item - The element to be added to the stack top.
See Also:
push
o push 
public abstract void push(Object item)
Add an element to top of stack.

Postcondition:
item is added to stack will be popped next if no intervening push

Parameters:
item - The value to be added to the top of the stack.
o remove 
public abstract Object remove()
Remove an element from the top of the stack.

Precondition:
stack is not empty
Postcondition:
most recently added item is removed and returned

Returns:
The item removed from the top of the stack.
See Also:
pop
o pop 
public abstract Object pop()
Remove an element from the top of the stack.

Precondition:
stack is not empty
Postcondition:
most recently pushed item is removed and returned

Returns:
A reference to the removed element.
o peek 
public abstract Object peek()
Fetch a reference to the top element of the stack.

Precondition:
stack is not empty
Postcondition:
top value (next to be popped) is returned

Returns:
A reference to the top element of the stack.
o empty 
public abstract boolean empty()
Returns true iff the stack is empty. Provided for compatibility with java.util.Vector.empty.

Postcondition:
returns true if and only if the stack is empty

Returns:
True iff the stack is empty.
See Also:
isEmpty
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