static void Main(string[] args)
{
Console.WriteLine("Hello C#!");
Kilogram kg1 = new Kilogram(5);
Kilogram kg2 = new Kilogram(10);
Kilogram kg3 = kg1.Add(kg2);
Kilogram kg4 = kg1 + kg2;
Console.WriteLine(kg3);
Console.WriteLine("연산자 오버로딩으로~" + kg4);
}
public Kilogram Add(Kilogram target)
{
return(new Kilogram(this.mass + target.mass));
}