Insert an object at the top of the Stack in C#

To insert an object at the top of the Stack, the code is as follows −

Example

 Live Demo

using System;
using System.Collections.Generic;
public class Demo {
   public static void Main() {
      Stack<int> stack = new Stack<int>();
      stack.Push(100);
      stack.Push(150);
      stack.Push(175);
      stack.Push(200);
      stack.Push(225);
      stack.Push(250);
      Console.WriteLine("Elements in the Stack:");
      foreach(var val in stack) {
         Console.WriteLine(val);
      }
      Console.WriteLine("Count of elements in the Stack = "+stack.Count);
      Console.WriteLine("Does Stack has the element 400?= "+stack.Contains(400));
      stack.Push(300);
      stack.Push(400);
      stack.Push(450);
      stack.Push(500);
      Console.WriteLine("Elements in the Stack... (UPDATED)");
      foreach(var val in stack) {
         Console.WriteLine(val);
      }
      Console.WriteLine("Count of elements in the Stack (UPDATED) = "+stack.Count);
   }
}

Output

This will produce the following output −

Elements in the Stack:
250
225
200
175
150
100
Count of elements in the Stack = 6
Does Stack has the element 400?= False
Elements in the Stack... (UPDATED)
500
450
400
300
250
225
200
175
150
100
Count of elements in the Stack (UPDATED) = 10

Example

Let us see another example −

 Live Demo

using System;
using System.Collections.Generic;
public class Demo {
   public static void Main() {
      Stack<string> stack = new Stack<string>();
      stack.Push("A");
      stack.Push("B");
      stack.Push("C");
      stack.Push("D");
      stack.Push("E");
      stack.Push("F");
      stack.Push("G");
      stack.Push("H");
      Console.WriteLine("Count of elements = "+stack.Count);
      Console.WriteLine("Elements in Stack...");
      foreach (string res in stack) {
         Console.WriteLine(res);
      }
      stack.Push("M");
      Console.WriteLine("Elements in the Stack... (UPDATED)");
      foreach(var val in stack) {
         Console.WriteLine(val);
      }
      Console.WriteLine("Count of elements in the Stack (UPDATED) = "+stack.Count);
   }
}

Output

This will produce the following output −

Count of elements = 8
Elements in Stack...
H
G
F
E
D
C
B
A
Elements in the Stack... (UPDATED)
M
H
G
F
E
D
C
B
A
Count of elements in the Stack (UPDATED) = 9