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

namespace ConsoleApplication1
{
class Program
{
static void Main(string[] args)
{
//Stack=stos
Stack stos = new Stack();

stos.Push(5);
stos.Push(7);
stos.Push(9);

Console.WriteLine(stos.Pop());
Console.WriteLine(stos.Pop());
Console.WriteLine();
Console.WriteLine(stos.Peek()); //sprawdza co jest na szczycie stosu
Console.ReadLine();
}
}
}




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

namespace ConsoleApplication1
{
class Program
{
static void Main(string[] args)
{
//Quese-kolejka
Queue kolejka = new Queue();


kolejka.Enqueue("pierwszy");
kolejka.Enqueue("drugi");
kolejka.Enqueue("trzeci");

Console.WriteLine(kolejka.Dequeue());
Console.WriteLine(kolejka.Dequeue());
Console.WriteLine();
Console.WriteLine(kolejka.Peek());
Console.ReadLine();

}
}
}




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

namespace ConsoleApplication1
{
class Program
{
static void Main(string[] args)
{
List lista = new List();
lista.Add(3);
lista.Add(5);
lista.Add(7);
lista.Add(5);


lista.Remove(5);
lista.RemoveAt(2);
lista.Insert(2, 8);
lista[2] = 5;
lista.Add(6);

for (int i = 0; i < lista.Count; i++)
{
Console.WriteLine( lista [i] );
}
Console.ReadLine();



}
}
}






ZADANIE
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace ConsoleApplication1
{
class Program
{
static void Main(string[] args)
{

Console.WriteLine(ONP("2 3 + 5 *"));
Console.ReadLine();
}

static int ONP(string wyrazenie)
{
Stack stos = new Stack();
string[] element = wyrazenie.Split(' ');

for (int i = 0; i < element.Length; i++)
{
if (element[i] == "+")
{
stos.Push(stos.Pop() + stos.Pop());
}
else if (element[i] == "*")
{
stos.Push(stos.Pop() * stos.Pop());
}
else
{
int liczba = Convert.ToInt32(element[i]);
stos.Push(liczba);
}


}



//int liczba= Convert.ToInt32(elemnty[i]);
//if(elementy =="+")
return stos.Pop();
}

}
}