Create factorial_iterative.py

Author: agarwalpranay02

maths/factorial_iterative.py

@@ -0,0 +1,16 @@
+def factorial_iterative(n: int) -> int:
+ """
+ Return the factorial of n using an iterative approach.
+ Raises ValueError for negative inputs.
+ """
+ if n < 0:
+ raise ValueError("Input must be a non-negative integer")
+ result = 1
+ for i in range(1, n + 1):
+ result *= i
+ return result
+
+
+if __name__ == "__main__":
+ # simple demonstration
+ print(factorial_iterative(5)) # expected 120