C# Stack

using System;

namespace Assignment
{
    class Program
    {
        static void Main(string[] args)
        {
            Stack stk = new Stack();
            stk.Pop();
            stk.Peek();
            stk.PrintStack();


            for (int i = 0; i < stk.GetCustomer().Length; i++)
            {
                Customer c = new Customer();
                stk.Push(c);
            }

            stk.PrintStack();



            Customer t = new Customer();
            stk.Push(t);



            for (int i = 0; i < 4; i++)
                stk.Pop();


            Console.WriteLine("Peek");
            stk.Peek();


            stk.Pop();
            stk.Peek();

        }
    }
}

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using System;
namespace Assignment
{
    class Customer
    {


		private string FirstName, LastName;

		public Customer()
		{
			Console.Write("Enter first name: ");
			FirstName = Console.ReadLine();
			Console.Write("Enter surname: ");
			LastName = Console.ReadLine();
		}


		public void SetFirstName(string firstName) { this.FirstName = firstName; }
		public void SetLastName(string lastName) { this.LastName = lastName; }


		public string GetFirstName() { return FirstName; }
		public string GetLastName() { return LastName; }

		public void PrintCustomer(int index)
		{
			Console.WriteLine($"Customer {index}: {FirstName} {LastName}");
		}
    }
}

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using System;
namespace Assignment
{

    class Stack
    {

        private int pointer;
        private Customer[] customers;


        public Stack()
        {
            Console.Write("Enter clients amount: ");
            int cAm = int.Parse(Console.ReadLine());
            customers = new Customer[cAm];
            pointer = 0;
        }


        public void SetPointer(int pointer) { this.pointer = pointer; }


        public Customer[] GetCustomer() { return customers; }

        public int GetPointer() { return pointer; }




        public bool IsFull()
        {
            if (pointer >= customers.Length) return true;
            else return false;
        }


        public bool IsEmpty()
        {
            if (pointer == 0) return true;
            else return false;
        }


        public void Push(Customer c)
        {
            if (IsEmpty() == true)
                Console.WriteLine("Can't push, no place.");
            else
            {
                customers[pointer] = c;
                pointer++;
            }
        }


        public Customer Pop()
        {
            if (IsEmpty() == true)
            {
                Console.WriteLine("Stack's empty.");
                return null;
            }
            else
            {
                Console.Write("Popping > ");
                customers[pointer - 1].PrintCustomer(pointer - 1);
                customers[pointer - 1].SetFirstName("");
                customers[pointer - 1].SetLastName("");
                pointer--;
                return null;
            }


        }


        public Customer Peek()
        {
            if (IsEmpty()==true)
            {
                Console.WriteLine("Stack's empty.");
                return null;
            }
            Console.WriteLine($"Last Customer: ");
            customers[pointer - 1].PrintCustomer(pointer - 1);
            return null;
        }


        public void PrintStack()
        {
            if (IsEmpty() == true)
                Console.WriteLine("Stack's empty.");
            else
            {
                for (int i = 0; i < pointer; i++)
                {
                    customers[i].PrintCustomer(i);
                }
            }


        }
     }

}