# Thread: New program need help with factorials

1. ## New program need help with factorials

I need to know how to find the factorial (5!=125) of a variable and, using it and for loops, put all of the possible combinations in an array.

I need to know how to find the factorial (5!=125) of a variable
Use a loop to calculate the factorial.

and, using it and for loops, put all of the possible combinations in an array.
Huh? Combinations of what into the array?

3. factorial of x is x*factorial(x-1), and factorial 0 is 1
have fun... I'd sugest a cicle instead of recursion... recursion does functions call, which have a big overhead and use lots of stack.

5!=125
Close... 5! = 120.

Do you know what a factorial is? Can you do it by hand or on a calculator? ... I mean a calculator without a factorial button.

5! means 1 x 2 x 3 x 4 x 5 = 120. (Of course, that's NOT C++ because x does NOT mean multiply in C++.)

Step 1
If you can't figure-out the whole program, how about starting with a loop that generates the sequential integers 1 thru n: 1, 2, 3, 4...

Step 2
When that's working, add the code to calculate the factorials.

Step 3
When you get that working, add the array stuff.

I assume that by "all the possible combinations" you mean this all of the factorials up to n: 1, 2, 6, 24...