C# Stack Example

Stack is a special type of collection object in C#, which stores elements in "Last in First Out" order, known as "LIFO style", c# provides generic and non-generic stack, in this tutorial, you learn how to declare a stack c#, create a stack c#, copy or clone a stack in c# with example

Stack can be non-generic and generic too. non-generic Stack class comes under System.Collections, and generic Stack class comes under System.Collections.Generic

how to use Stack in C# programming?

Stack is a special type of collection in C#, which stores elements in LIFO style(Last In First Out). C# includes a generic and non-generic Stack. Here you will learn about the non-generic stack.

Stack allows duplicate values and also null value, Stack comes under System.Collections namespace

• Initializes a new instance of the Stack class (non-generic)

  using System.Collections;
  Stack myStack = new Stack();
  

  Initializes a new instance of the Stack class (generic)

  using System.Collections.Generic;
  Stack<string> s = new Stack<string>();
  

• Peek

  Returns the top item from the stack.

• Pop

  Removes and returns items from the top of the stack.

• Contains

  Checks whether an item exists in the stack or not

• Push

  Inserts an item at the top of the stack.

• Clear

  Removes all items from the stack.

Push method allows adding object in stack object, so in example below we have created a new instance of stack object, and then added different type of values.

using System.Collections;
Stack myStack = new Stack();
myStack.Push(1);
myStack.Push(1.10);
myStack.Push("this is a string");
myStack.Push(DateTime.Now);
myStack.Push(null);

As you can see in above code we have created a stack object called “myStack”, then added few values using push method, now we retrieve those values by looping throw the stack collection object.

foreach (var itm in myStack)                
{
Console.Write(itm);
}

Peek method is for retrieving value from stack object, for example, now we want to read the value from above stack collection object "myStack".

Console.WriteLine(myStack.Peek());

The Pop() method removes and returns the value that was added last to the Stack.

using System.Collections;
Stack popStack = new Stack();
popStack.Push(1);
popStack.Push(2);
popStack.Push(3);
popStack.Push(4);
Console.Write("Total elements in Stack: {0}", popStack.Count);
while (myStack.Count > 0)
    Console.WriteLine(popStack.Pop());             
    Console.Write("Total elements in Stack: {0}", popStack.Count);

After executing the above code, the result would be

Total elements in Stack: 4
4
3
2
1
Total elements in Stack: 0

Stack and Queue are both collection objects, they come under System.Collection namespace, but there are some differences

• Queue class maintain objects in collection on First-in First-Out basis (FIFO)
• Stack class maintain objects in collection on First-in Last-Out basis (FILO)

You should also look at others C# Data Structures Fundamental.