Notes

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

namespace ConsoleApp1
{
class Dikdörtgen
{
private double _en;
public double En
{
get => _en;
set => _en = value;
}
private double _boy;
public double Boy
{
get => _boy;
set => _boy = value;
}

public double Alan()
{
return En * Boy;
}
}
}

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

namespace ConsoleApp1
{
class kare
{
private double _kenar;
public double Kenar
{
get => _kenar;
set => _kenar = value;
}

public double KareAlan()
{
return Kenar * Kenar;
}
}
}

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

namespace ConsoleApp1
{
class AlanHesaplayıcı
{
public void alanhesapla(int cevap)
{
switch (cevap)
{
case 1:
kare Kare = new kare();
Console.Write("Kenar uzunluğu giriniz:");
Kare.Kenar = Convert.ToInt32(Console.ReadLine());
Console.WriteLine("Karenin alanı:"+Kare.KareAlan());
break;

case 2:
Dikdörtgen dikdörtgen = new Dikdörtgen();
Console.Write("Enini giriniz:");
dikdörtgen.En = Convert.ToDouble(Console.ReadLine());
Console.Write("Boyunu giriniz:");
dikdörtgen.Boy = Convert.ToDouble(Console.ReadLine());
Console.WriteLine("Dikdörtgenin alanı:"+dikdörtgen.Alan());
break;
case 3:
Cember cember = new Cember();
Console.Write("Yarıçapını giriniz:");
cember.Yaricap = Convert.ToDouble(Console.ReadLine());

Console.WriteLine("Çemberin alanı :" +cember.Alan());
break;

}
}
}
}

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

namespace ConsoleApp1
{
class Cember
{
public double pi = 3.14;
private double _yaricap;
public double Yaricap
{
get => _yaricap;
set =>_yaricap = value;
}

public double Alan()
{
return pi * (Yaricap * Yaricap);
}
}
}

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

namespace ConsoleApp1
{
class Program
{
static void Main(string[] args)
{
bool devam = true;
AlanHesaplayıcı alan = new AlanHesaplayıcı();
while (devam)
{
Console.WriteLine("***********************************");
Console.WriteLine("1-kare alan hesaplama");
Console.WriteLine("2-dikdörtgen alan hesaplama");
Console.WriteLine("3-çember alan hesaplama");
Console.WriteLine("4-çıkış");

int secim = Convert.ToInt32(Console.ReadLine());
alan.alanhesapla(secim);

if (secim == 4)
{
devam = false;
}


}
Console.ReadKey();
}
}
}