C#

Create an array that contains all two-digit numbers from 10 to 99. Print the following:

1) The length of this array;

2) The first element;

3) The last element;

4) The middle element;

5) The sum of all the values using a loop;

6) The number of even values using a loop;

7) Count the number of teens that occur in the number (e.g. thirteen) using a loop;

8) Change all the elements that are tens (e.g. 10, 20, 30, etc) in the array to 0 using a loop;

9) Print all the elements in the array with each element separated by a space; and

10) Print the average of the array as a decimal value.