Goal: Learn how to read an array from a file and process the data.

Assignment: Write a function named expandArray. The function should accept an array of type int and the array$$s size as arguments. The function should perform the following steps:

The function should create a new int array that is twice the size of the argument array.

The function should copy the contents of the argument array to the new array and initialize the unused elements of the second array with $0.$

The function should return a pointer to the new array.

If the size of the argument array is $0$ or negative, the expandArray function should return nullptr.

Note: Do not write a complete program. Write only the code for the expandArray function. Please use c$++$