Answer:
zero
Explanation:
Because of the define the product variable is zero.
when the function call with pass by value 4.
The program control moves to that function, after that product
store the value zero. Then, product is multiply with n which become zero
because 0 * n is zero and store in the product again.
after that, n'' is wrong it must be 'n--' for performing the factorial function.
after that, the value of n is 3, again loop execute because condition n > 0
is true.
again zero multiply with n and become zero.
this process repeated until condition false and finally the output is zero.
Correction:
To make the code working:
change product = 1 instead of zero.
and change n-- in place of n''.
