Chapter 20, Problem 9ICA

Write a function named EvenSum that will accept a matrix of unknown size and return the sum of all elements at the intersection of even numbered rows and even numbered columns. Note that your function must work with any sixe matrix. Also note that if the matrix is a scalar or a vector, the function will return zero since there are no even numbered rows or columns in those cases. Accomplish this using two methods:

a.    a for loop without using built-in functions like sum

b.    direct matrix operations, no loops

EXAMPLE: For the matrix shown, A=EvenSum(Test); will place the value 13 in A.

The numbers added together are shown in red.

     $=\left[\begin{array}{ccccc}1& 3& 5& 7& 9\\ 0& 1& 2& 3& 4\\ 6& 4& 2& 1& 8\\ 3& 5& 2& 4& 0\end{array}\right]$