Stack (C#)

Stack

A generic collection in System.Collections.Generic that stores elements for last-in, first-out (LIFO) processing. Domain: C# → .NET → System.Collections.Generic → Stack

LIFO

Last In, First Out; the most recently added element in a Stack is the next element removed.

Top of a Stack

The end of a Stack where elements are added, inspected, and removed.

Bottom of a Stack

The end of a Stack containing the elements that have been stored the longest.

new Stack()

Creates an empty Stack.

new Stack(collection)

Creates a Stack containing elements copied from the specified collection.

stack.Count

Gets the number of elements currently contained in the Stack.

stack.Push(item)

Adds an element to the top of the Stack.

stack.Pop()

Removes and returns the element at the top of the Stack; throws InvalidOperationException if the Stack is empty.

stack.Peek()

Returns the element at the top of the Stack without removing it; throws InvalidOperationException if the Stack is empty.

stack.TryPop(out result)

Attempts to remove and return the top element, returning false if the Stack is empty.

stack.TryPeek(out result)

Attempts to return the top element without removing it, returning false if the Stack is empty.

stack.Contains(item)

Determines whether the specified element occurs in the Stack.

stack.Clear()

Removes all elements from the Stack.

stack.ToArray()

Copies the Stack elements into a new array with the top element first.

stack.TrimExcess()

Reduces excess internal storage capacity when appropriate relative to the number of elements currently stored.

Push vs Pop

Push adds an element to the top of a Stack, whereas Pop removes and returns the element from the top.

Pop vs Peek

Pop returns and removes the top element, whereas Peek returns the top element without removing it.

TryPop vs Pop

TryPop safely reports failure when the Stack is empty, whereas Pop throws an InvalidOperationException.

Stack vs Queue

Stack uses LIFO processing, where the newest element leaves first; Queue uses FIFO processing, where the oldest element leaves first.