$1.$ Write a C$++$ program that does the following:

a$.$ Create a C$++$ file with the name problem$2.$cpp$.$

b$.$ Prompt the user for an odd positive integer n$,$ terminating the program if the user enters an invalid integer.

c$.$ Print an n x n grid displaying a large letter X with the following properties:

a$.$ The left half of the X using the character $+$

b$.$ The right half of the X using the character x

c$.$ The middle line using the character $*$

Sample run of the program:

Enter an odd positive integer for n: $7$

$+$x

$+$x

$+$ x

$*$

$+$ x

$+$x

$+$x