C# struct

C#  struct

struct Point{
  public  int X;
  public  int Y;
}

var p1= new Point(){X=1,Y=1}

var p2= new Point(){X=1,Y=1}
p1.X=123;

var p3=p1;

hashcode  of p1 and p2 is the same!

if p1 change its` some property, the hashcode will change!

hashset<point> can work when we need judge repeat

if we change the struct into class, all will reverse!