IStack Interface
The IStack interface defines a collection of objects that follows the last‑in, first‑out (LIFO) principle. It provides methods for pushing and popping elements.
Methods
| Signature | Description |
|---|---|
void Push(object obj) | Inserts an object at the top of the stack. |
object Pop() | Removes and returns the object at the top of the stack. |
object Peek() | Returns the object at the top of the stack without removing it. |
bool IsEmpty { get; } | Gets a value indicating whether the stack is empty. |
int Count { get; } | Gets the number of elements contained in the stack. |
Properties
| Signature | Description |
|---|---|
bool IsEmpty { get; } | Indicates if the stack contains no elements. |
int Count { get; } | Number of elements in the stack. |
Remarks
Implementations of IStack must provide thread‑safe operations if they are to be used concurrently. The interface does not prescribe a specific underlying data structure; typical implementations use arrays or linked lists.
Example
// Example of a simple stack implementation
class SimpleStack : IStack
{
private readonly List<object> _items = new();
public int Count => _items.Count;
public bool IsEmpty => Count == 0;
public void Push(object obj) => _items.Add(obj);
public object Pop()
{
if (IsEmpty) throw new InvalidOperationException("Stack empty");
var top = _items[^1];
_items.RemoveAt(_items.Count - 1);
return top;
}
public object Peek()
{
if (IsEmpty) throw new InvalidOperationException("Stack empty");
return _items[^1];
}
public IEnumerator GetEnumerator() => _items.GetEnumerator();
}