Data Structures, Algorithms, & Applications in C++
Chapter 1, Exercise 19

The code for the iterative function factorial is given below and in the file iterativeFactorial.cpp.

int factorial (int n)
{// Return n!.
   if (n <= 1)
      return 1;
   int fact = 2;
   for (int i = 3; i <= n; i++)
      fact *= i;
   return fact;
}