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

namespace CK_Assessment3
{


    ///<summary>
    /// anarray based list for integers
    ///</summary>
    class IntArrayList
    {



        private int count;


        private int[] values;


        //Default Constructor setting maximum size of list to 20
        public IntArrayList()
        {
            values = new int[20];
            count= 0;
        }

       //Overloaded Constructor
        public IntArrayList(int capacity)
        {
            values = new int[capacity];
            count = 0;
        }



        //Check to see if list is empty
        public bool isEmpty()
        {
            return(count==0); //
        }

        //Checks to see if list is full
        public bool isFull()
        {
            return values.Length==count; //Return full if no more space

        }

        //Adds value to first postition of array list
        public void addFirst(int value)
        {
            if(isFull())
            {
                throw new Exception("list full"); //Error message display if  list is full
            }
            if(isEmpty())
            {
                addLast(value);  //Adds value to first postion
            }
            else
            {
                for(int pos =count;pos>0;pos--)
                {
                    values[pos]=values[pos-1]; ////Loops through list, decrementing position in list by 1
                }
                values[0]=value; //Sets first value in list to new value entered
                count++; //Count increased by 1
            }
          }


        //Adds value to last position
        public void addLast(int value)
        {
            if(isFull())
            {
                throw new Exception("list full"); //Checks if list is full, displays message if full
            }
            values[count]=value; //Sets last value in list to new value entered
            count++;

        }

        //Removing last value
        public int removeLast()
        {

            if(isEmpty())
            {
                throw new Exception("list Empty"); //Checks if list is empty, displays message if empty
            }

            int popValue=values[count-1];  //Removes last value from list
            count--;
            return popValue; //Returns value that is removed

        }

        //Returns size of list
        public int size()
        {
            return count;
        }

        //consoleUI for testing
        public void display()
        {
            if(count==0)
                Console.WriteLine("list is empty");
            else
            {
                Console.WriteLine("list has"+ count+"items");
                for(int i = count-1;i>=0;i--) Console.WriteLine("value:"+ values[i]);
            }
        }

  }
}