$3.$ The factorial of a non$-$negative integer x$,$ expressed as x$!,$ refers to x multiplied by the

product of all integers less than x$,$ down to $1.$

Formally, it is written like this:

$$x factorial$=$ x$!=$ x $($x $1)($x $2)...1$

Note that there is a special case of zero factorial, which is always $1.$ That is:

$0!=1$

For example, to work out $3$ factorial, you compute the following:

$321=6$

To work out $7$ factorial, you compute the following:$7654321=5040$

Write a function containing a loop that computes and stores as a new object the factorial of any

non$-$negative integer mynum by decrementing mynum by $1$ at each repetition of the braced

code. Return an object containing the factorial of mynum $($mynum$\_$fac$),$ and show the contents

of mynum$\_$fac outside the main function.

Using your function, compute the factorial:

a$.$ mynum$=5$

b$.$ mynum$=14$

c$.$ mynum $=-1$