Exercise $9$: Practice some of these methods for accessing matrix elements with the following exercises:

Create a matrix of size $NN$ that has ones in the border and zeros inside. For example if $N=3$ the matrix can be created with

$>>$ A$=$ones$(3,3)$; A$(2,2)=0$

Make this construction depend on $N$ and work for any positive integer $N2$

Create a $55$ matrix whose rows are $(1$:$5)$

Extract the diagonal of a given matrix without using diag $($you may use size$)$

Flip a given matrix horiztonally. Vertically? Do not use fliplr or flipud

Extract the anti$-$diagonal of a given matrix

Extract the anti$-$djagonal, without first flipping it $($Hint: use single index access$)$