Write a C$++$ program to add the elements on the two diagonals of a square two$$ dimensional integer array and display that sum. Ensure that if there is a middle element in the array it is not counted twice in the sum.

For example, with the array:

$1234$

$5678$

$9101112$

$13141516$

your program should display $68(1+6+11+16+4+7+10+13).$

With the array:

$123$

$567$

$91011$

your program should display $30(1+6+11+3+9)($note that the $6$ is not counted twice$).$