Difference between the System.Array.CopyTo() and System.Array.Clone()

The Clone() method returns a new array (a shallow copy) object containing all the elements in the original array. The CopyTo() method copies the elements into another existing array. Both perform a shallow copy. A shallow copy means the contents (each array element) contains references to the same object as the elements in the original array. A deep copy (which neither of these methods performs) would create a new instance of each element's object, resulting in a different, yet identical object.

So the difference are :

1- CopyTo require to have a destination array when Clone return a new array.
2- CopyTo let you specify an index (if required) to the destination array.

Remove the wrong example.

One other difference not mentioned so far is that

• with Clone() the destination array need not exist yet since a new one is created from scratch.
• with CopyTo() not only does the destination array need to already exist, it needs to be large enough to hold all the elements in the source array from the index you specify as the destination.

Both perform shallow copies as @PatrickDesjardins said (despite the many misled souls who think that CopyTo does a deep copy).

However, CopyTo allows you to copy one array to a specified index in the destination array, giving it significantly more flexibility.

Array.Clone() would perform technically deep copy, when pass the array of int or string to a method as a reference.

For example

int[] numbers = new int[] { -11, 12, -42, 0, 1, 90, 68, 6, -9 }; 

SortByAscending(numbers); // Sort the array in ascending order by clone the numbers array to local new array.
SortByDescending(numbers); // Same as Ascending order Clone

Even if the methods sort the array of numbers but it wont affect the actual reference passed to the sorting methods.i.e the number array will be in same unsorted initial format in line no 1.

Note: The Clone should be done in the sorting methods.

Array.Clone doesn't require a target/destination array to be available when calling the function, whereas Array.CopyTo requires a destination array and an index.

Clone() is used to copy only structure of data/array it doesn't copy the actual data.

CopyTo() copies the structure as well as actual data.