The factorial function is defined like this: The factorial of both $0$ and $1$ is $1$, and the factorial of numbers
larger than $1$ are found like this:

In this lesson, as more practice on how to write functions, we'll implement a factorial function. Remember, given a number $n$, the factorial is $n\times (n-1)\times (n-2)\times 1$. But if you look at a bit differently, you'll also see that $n!=1\times 2\times 3\times 4\times n$. This second definition is easiest to implement using a single for-loop. Use a for-loop to multiply the numbers from 1 to $n$ together.

See if you can complete the factorial function below. As for testing, be sure you get that

- The factorial of $2$ is $2\times 1=2$
- The factorial of $3$ is $3\times 2\times 1=6$
- The factorial of $4$ is $4\times 3\times 2\times 1=24$.

In this lesson, as more practice on how to write functions, we'll implement a factorial function. Remember, given a number $n$, the factorial is $n\times (n-1)\times (n-2)\times 1$. But if you look at a bit differently, you'll also see that $n!=1\times 2\times 3\times 4\times n$. This second definition is easiest to implement using a single for-loop. Use a for-loop to multiply the numbers from 1 to $n$ together.

See if you can complete the factorial function below. As for testing, be sure you get that

`fact(5)=120`

and `fact(10)=3628800`

. Note: We have an actual use for the factorial in a future lesson.
`for i=??? do`

line and the `p=p*`

line to handle the factorial as described above.
Type your code here:

See your results here:

This code will not run! Fix the for loop. What will you have it count over? Next, fix the

`p=p *`

line to keep track
of the rolling factorial product (p for "product").