Write a complete C$++$ program that does the following:

$-$ ask the user to enter an odd positive integer.

$-$ Input the value into a variable called num

$-$ If the value is not legal:

$-$ the program terminates.

$-$ print a num x num grid displaying a large letter $\backslash ($ X $\backslash )$

$-$ The left half of the $\backslash ($ X $\backslash )$ should be made with the character $+$

$-$ the right half should be made with the character $\backslash (\backslash$mathbf$\{$x$\}\backslash )$

$-$ the center should be a $*$

A sample run of the program:

$```$

Enter value for n: $7$

$+$ x

$+$ x

$+$x

$*$

$+$ x

$+$ x

$+$ x

$```$