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Stacks

A stack is a Last In, First Out (LIFO) collection of elements where the last element that goes into the stack will be the first element that comes out.

Inserting an element onto a stack is called pushing. Deleting an element from a stack is called popping. Pushing and popping can be performed only at the top of the stack.

Stacks can be used to create undo-redo functionalities, parsing expressions (infix to postfix/prefix conversion), and much more. The C# generic collection Stack<T> class requires all elements to be of the same type T.

Add (push) to Stack​

var stack = new Stack<int>();

// Hinzufügen von Elementen (Push)
stack.Push(10);
stack.Push(20);
stack.Push(30);

Anzahl Elemente im Stack​

Console.WriteLine($"Anzahl der Elemente: {stack.Count}");

Zugriff auf Elemente (peek, pop)​

// Zugriff auf das oberste Element ohne es zu entfernen (Peek)
Console.WriteLine($"Oberstes Element (Peek): {stack.Peek()}");

// Entfernen des obersten Elements (Pop)
Console.WriteLine($"Entferntes Element (Pop): {stack.Pop()}");

TryPeek und TryPop​

if (stack.TryPeek(out int topElement))
{
	Console.WriteLine($"\nOberstes Element (TryPeek): {topElement}");
}

if (stack.TryPop(out int poppedElement))
{
	Console.WriteLine($"Entferntes Element (TryPop): {poppedElement}");
}

Stack leeren​

stack.Clear();
Console.WriteLine($"\nAnzahl der Elemente nach Clear: {stack.Count}");