Recursion in c++ Factorial Program

Question

hello i have this piece of code that i coded based on some other recursion and factorial programs but my problem is that i am really confused as to how it stored the value a

Answer 1

Well, the factorial function can be written using recursion or not, but the main consideration in the recursion is that this one uses the system stack, so, each call to the function is a item in the system stack, like this (read from the bottom to the top):

Other consideration in the recursion function is that this one has two main code piece:

1. The base case
2. The recursion case

In the base case, the recursive function returns the element that bounds the algorithm, and that stop the recursion. In the factorial this element is 1, because mathematically the factorial of number one is 1 by definition. For other numbers you don't know the factorial, because of that, you have to compute by using the formula, and one implementation of it is using recursion, so the recursive case.

Example: The factorial of 5, the procedure is: 5*4*3*2*1 = 120, note you have to multiply each number from the top value until number 1, in other words, until the base case takes place which is the case that you already knew.