Search code examples
c#arrayscopy

Copy Arrays to Array

I have a little problem with arrays. I am new in C#.

I try to copy an int array into two other int arrays with

unsortedArray = randomNumbers();

unsortedArray2 = unsortedArray;
unsortedArray3 = unsortedArray;

But, if I sort the unsortedArray2, the unsortedArray3 is sorted too.

Can someone help me?

Solution

  • I try to copy a Int Array into 2 other Int Arrays with

    The first thing that is important is that in this line :

    unsortedArray2 = unsortedArray;

    you do not copy the values of the unsortedArray into unsortedArray2. The = is called the assignment operator

    The assignment operator (=) stores the value of its right-hand operand in the storage location,

    Now the second thing that you need to know to understand this phenomenon is that there are 2 types of objects in C# Reference Types and Value types

    The documentation explains it actually quite nicely:

    Variables of reference types store references to their data (objects), while variables of value types directly contain their data. With reference types, two variables can reference the same object; therefore, operations on one variable can affect the object referenced by the other variable.

    The solution can be to use the Array.Copy method.

    Array.Copy(unsortedArray, 0, unsortedArray2 , 0, unsortedArray.Length);

    The CopyTo method would also work in this case

    unsortedArray.CopyTo(unsortedArray2 , 0);

    Note:this will work because the content of the array is a value type! If it would be also of reference type, changing a sub value of one of the items would lead also to a change in the same item in the destination array.