Factorial Function | Dataford Interview Questions

A calculation within Bank of America Mobile Banking needs to evaluate factorial values for small nonnegative integers. Write a function that returns the factorial of n, written as n! = n × (n - 1) × ... × 1.

Use an iterative approach and do not call Python's built-in factorial function.

Formal Specification

Implement factorial(n), where n is an integer. Return an integer equal to the product of every integer from 1 through n. By definition, 0! equals 1.

Constraints

0 <= n <= 20
n is an integer
The result fits within a signed 64-bit integer
Do not use Python's built-in factorial function

Function Signature

def factorial(n):

Your question is Factorial Function. Start with the requirements in the Question tab.

Run and submit as often as you like. When you're ready, talk me through your approach or go straight to the code.

Problem