using System;
namespace VietJackCsharp
{
class Rectangle
//cac bien thanh vien
internal double length;
internal double width;
//cac phuong thuc
double GetArea()
return length * width;
}
public void Display()
Console.WriteLine("Chieu dai: {0}", length);
Console.WriteLine("Chieu rong: {0}", width);
Console.WriteLine("Dien tich: {0}", GetArea());