Difference between array.GetLength(0) and array.GetUpperBound(0)

Question

What is the difference between these two methods and when would you use one instead of the other?

int[,] array = new int[4,3];
int length0 = array.GetLength(         


        

Answer 1

GetUpperBound returns the highest index in the array, the GetLength returns the number of elements of the array.

i.e. GetUpperBound = GetLength - 1