Saturday, 18 February 2017

Stack DataStructure


Introduction:  
Stack is an abstract data type. It serves as a collection of elements and follow LIFO(last in first out) pattern. So every new added item goes on the top of the stack, and only top item can be removed first.
 It has main 2 operations
 push: This operation adds an element to the collection at the top
 pop: It removes the most recently added element that was not yet removed.


using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;



namespace Stack
{
    public interface IStack<T>
    {
       void Push(T element);
        T Pop();
        void Print();
    }



    public class Stack<T> : IStack<T>
    {
        private T[] _items = new T[10] ;
        private int _top = -1;
        public void Push(T element)
        {
            if (_top < 9)
            {



                _items[++_top] = element;
                
            }
            else
            {
                throw new Exception("Stack is full. Item can't be added.");
            }
        }



        public void Print()
        {
            for (int i = _top; i > -1; i--)
            {
                Console.WriteLine("index:{0} item:{1}",i,_items[i]);
            }
        }





        public T Pop()
        {
            if (_top == -1)
            {
                throw new Exception("Stack is empty.");
            }
            return _items[_top--];
        }



    }


    public class Program
    {
        public static void Main(string[] args)
        {
            var stack = new Stack<int>();
            stack.Push(110);
            stack.Push(101);
            stack.Push(111);
            stack.Print();
            var item = stack.Pop();
            Console.WriteLine("Poped item :: {0}",item);
            stack.Print();
            stack.Push(200);
            stack.Print();
            Console.ReadKey();
        }
    }  

}

Complexity Analysis
                                push,pop: O(1) & search: O(n)
   


No comments:

Post a Comment