I know that CopyTo requires to have a destination array while Clone returns a new array. but i have read that both perform shallow copy and refer same instance..
So if I have
A = [1,2,3,4]
and I Clone it and get
B = [1,2,3,4].
Now, if I change
B[0] = 9.
This means that A will now be
A = [9,2,3,4].
Is that correct? And is this correct for CopytTo()?
When you do B[0] = 9 you are replacing element with 0 index in B array, so A array will stay the same (you don't change it actually) and it doesn't matter which method (CopyTo or Clone) you are using (since A doesn't reference to B).
No. Clone typically creates a new instance and copy whatever in the original object to it. Other words, A and B are pointing at two different memories. In your case, A will remain the intact.
A = [1, 2, 3, 4]
A will only be changed if we set
B = A;
In this case, both A and B are pointing at the same address.
However, if we set
B = A.Clone();
Then whatever changes made to B will not affect A. CopyTo also does the same process as Clone except that it lets you specify the position in A to start copying data to B.
The MSDN documentation of Array.Clone specifically goes through this example to show that no it will not change both copies.
This makes sense, as the array object will be a series of memory addresses pointing to the object. When you clone the array, you create a copy of the memory addresses. If you change one of the arrays, you change the value of the memory address. Hence the change will be comfined to that array.
http://msdn.microsoft.com/en-us/library/system.array.clone(v=vs.110).aspx
