Your task is to write a MATLAB function that enumerates the neighbors of a rectangle in an $mn$ mesh of

rectangles. Assume that the rectangles are numbered starting at $1$ in the upper left corner and

increasing from left to right and top to bottom as shown in the example.

Your function should be called getNeighbors. It should take exactly three input arguments in this

order: $m,n,$ and $r.$ Here $m$ is the number of rows in the mesh, $n$ is the number of columns, and $r$ is the

rectangle whose neighbors must be identified. The function should return exactly one argument, an

array containing the numbers of the neighbors in increasing order. Write your code so that the array is

directly generated in the correct order; do not use the sort function. For example,

getNeighbors $(4,6,14)$ should return the array $\left[\begin{array}{cccccccc}7& 8& 9& 13& 15& 19& 20& 21\end{array}\right].$

Your program should validate the input arguments and return and empty array $($i$.$e$.,[])$ if any of the

inputs are invalid. More specifically, your program must check that $m$ and $n$ are not less than $2,r$ is the

number of a rectangle that exists in the mesh, and all input values are integers. For example, the

following should return an empty array because there is no rectangle with number $100$ for the given

mesh size: getNeighbors $(4,6,100).$

Test your function using the testGetNeighbors test stub.