Start implementing Stack

Author: hamednikzad

README.md

@@ -1,2 +1,9 @@
 # pure-data-structures-and-algorithms-csharp
 Data structures and algorithms implementation in pure csharp
+
+Data structures that have been implemented so far:
+- Arrays Introduction
+- Array List
+- List List
+- Singly Linked List
+- Doubly Linked List

TODO.md

@@ -18,6 +18,8 @@ Here is Data Structures base on https://en.wikipedia.org/wiki/List_of_data_struc
 - [ ] Queue (example Priority queue)
 - [ ] Double-ended queue
 - [ ] Graph (example Tree, Heap)
+- [ ] Hash Table
+- [ ] Dictionary
 
 ### Linear 
  - [ ] Array
@@ -42,13 +44,13 @@ Here is Data Structures base on https://en.wikipedia.org/wiki/List_of_data_struc
  - [ ] Variable-length array
  - [ ] List
  - [x] Singly Linked List
- - [ ] Doubly Linked List
+ - [x] Doubly Linked List
  - [ ] Circular Linked List
  - [ ] Doubly Circular Linked List
  - [ ] header Linked List
  - [ ] Doubly linked list
  - [x] Array list
- - [ ] Linked list
+ - [x] Linked list
  - [ ] Association list
  - [ ] Self-organizing list
  - [ ] Skip list

src/ConsoleApp/Program.cs

@@ -4,7 +4,7 @@
 //ArrayUsage();
 //ArrayListUsage();
 //ListUsage();
-//SinglyLinkedListUsage();
+SinglyLinkedListUsage();
 DoublyLinkedListUsage();
 
 void ArrayUsage()
@@ -49,6 +49,7 @@ void SinglyLinkedListUsage()
  Console.WriteLine(i);
  }
 
+ var last = ll[2];
  ll.Remove(1);
 }
 

src/DataStructures/AbstractDataTypes/Lists/NikDoublyLinkedList.cs

@@ -131,6 +131,26 @@ public void Remove(int index)
 
  _count--;
  }
+
+ public T this[int index]
+ {
+ get
+ {
+ if (_head is null || index < 0 || index > _count)
+ throw new ArgumentOutOfRangeException(nameof(index), "Out of range");
+
+ var i = 0;
+ var current = _head;
+ while (i != index && current is not null)
+ {
+ current = current.Next;
+ 
+ i++;
+ }
+
+ return current!.Value;
+ }
+ }
 
  public bool RemoveValue(T value)
  {

src/DataStructures/AbstractDataTypes/Lists/NikList.cs

@@ -11,11 +11,6 @@ public class NikList<T> : IEnumerable<T>
  private int _capacity;
  private readonly T[] _emptyArray = Array.Empty<T>();
 
- public void CopyTo(Array array, int index)
- {
- throw new NotImplementedException();
- }
-
  public int Count => _size;
 
  public int Capacity => _capacity;

src/DataStructures/AbstractDataTypes/Lists/NikSinglyLinkedList.cs

@@ -88,6 +88,26 @@ public void Remove(int index)
 
  _count--;
  }
+
+ public T this[int index]
+ {
+ get
+ {
+ if (_head is null || index < 0 || index > _count)
+ throw new ArgumentOutOfRangeException(nameof(index), "Out of range");
+
+ var i = 0;
+ var current = _head;
+ while (i != index && current is not null)
+ {
+ current = current.Next;
+ 
+ i++;
+ }
+
+ return current!.Value;
+ }
+ }
 
  public bool RemoveValue(T value)
  {

src/DataStructures/AbstractDataTypes/Stacks/NikStack.cs

@@ -0,0 +1,86 @@
+namespace DataStructures.AbstractDataTypes.Stacks;
+
+public class NikStack<T>
+{
+ private T[] _items;
+ private int _top;
+ private int _capacity;
+ private readonly T[] _emptyArray = Array.Empty<T>();
+
+ public int Count => _size;
+
+ public int Capacity => _capacity;
+
+ public NikStack()
+ {
+ _items = _emptyArray;
+ _capacity = 0;
+ }
+
+ public NikStack(int capacity)
+ {
+ if (capacity < 0)
+ throw new ArgumentOutOfRangeException(nameof(capacity), "Should be non negative");
+
+ _items = capacity == 0 ? _emptyArray : new T[capacity];
+
+ _capacity = capacity;
+ }
+ 
+ private void CheckCapacity(int size)
+ {
+ if (_items.Length >= size)
+ return;
+ int newCapacity = _items.Length == 0 ? 4 : _items.Length * 2;
+ if ((uint) newCapacity > Array.MaxLength) newCapacity = Array.MaxLength;
+ if (newCapacity < size) newCapacity = size;
+
+ ChangeCapacity(newCapacity);
+ }
+
+ private void ChangeCapacity(int newCapacity)
+ {
+ if (newCapacity < -_size)
+ throw new ArgumentOutOfRangeException(nameof(newCapacity), "Out of range");
+
+ if (newCapacity == _capacity)
+ return;
+
+ if (newCapacity > 0)
+ {
+ var newItems = new T[newCapacity];
+
+ if (_size > 0)
+ {
+ Array.Copy(_items, 0, newItems, 0, _size);
+ }
+
+ _items = newItems;
+ }
+ else
+ {
+ _items = _emptyArray;
+ }
+
+ _capacity = newCapacity;
+ }
+
+ public void Push(T value)
+ {
+ if (_size == _items.Length) CheckCapacity(_size + 1);
+
+ _top++;
+ _size++;
+ _items[_top] = value;
+ }
+
+ public T Pop()
+ {
+ 
+ }
+
+ public T Peek()
+ {
+ 
+ }
+}