How to make "combinations" (Math)

Question

How to make combinations and permutations?

C = ( (n +r -1)! ) / r! * (n - 1)!
or C = n! / (n - 1)

In gdscript there is no operator " ! "

Comments

Maybe there is an operator similar to "!"? It would help me.

Answer 1

You would use a loop and a method. I am only writing some pseudocode to get you along:

def factorial(n):
    int product = 1
    for int i = 1; i<n+1; ++i:
        product = product*i
    return product

then you don't need the ! operator. For example writing n!/(n-1) = factorial(n)/(n-1)