Can anyone please clarify this basic query

Question

Hi all Im very new to .net. I have opted this site to learn. Now when Im going through the tutorials i made small code snippet for practice.
class myclass
{
   int no;
   string st;
}
main()
{
   myclass temp = new myclass();
   myclass ab = new myclass():
   temp.no = 1;
   temp = ab;
   temp.no = 2;
   ab.no =3;

   After here no matter how changes i make to ab.. itz effecting temp also.. I understand it is taking as a reference. But please clarify me that if i want only contents to be copied what should I do.. Please dont mind I know Im asking very basic silly doubt.. Understand my prblem becoz I have come from C background.. Im getting hard to understand C#.

}

mahesh gupta · Answer

now I understand.. so we do have the same problem of deep copy and shallow even in the case of C#.. No escape Thanks for the replies. Im happy to see the instant reply..

Vulpes · Answer

You could also create a Clone() method for myclass: using System; class myclass { public int no; public string st; public myclass Clone() { return (myclass)this.MemberwiseClone(); } } class Program { static void Main() { myclass temp = new myclass(); temp.no = 1; myclass ab = temp.Clone(); ab.no = 3; Console.WriteLine(temp.no); // still 1 Console.ReadKey(); } } Incidentally, MemberwiseClone() creates a 'shallow' copy which is OK as long as your fields are all value types (int, double etc) or strings. You'd need to clone any reference type fields individually.

mahesh gupta · Answer

ok.. if its two members we can do.. but if it contains a huge set of members what should we do. Do we need to write some function in the myclass to do a copy of indiviudal elements as we do in copy constructor in C++

Guest User · Answer

Don't worry, Mahesh... object references can be a bit tricky to understand for newcomers. When these two lines execute: myclass temp = new myclass(); myclass ab = new myclass(): You have two separate instances of myclass. But after this line: temp = ab; The variables temp and ab both point to the ab instance. The instance that was originally assigned to temp is no longer accessible and will be garbage-collected by .Net. To copy one instance's properties to another, the quickest way would be to do something like this: temp.no = ab.no; // copies the no value from ab to temp temp.st = ab.st; // copies the st string reference from ab to temp

Can anyone please clarify this basic query

Answers (4)