The document describes a program to calculate the factorial of a given integer using a non-recursive function. The main program reads an integer value and calls the sub-program fact(n). The sub-program initializes f to 1, checks if n is 0 or 1 and returns 1. Otherwise, it performs a loop from i=1 to n, multiplying f by i each iteration. It returns f to the main program, which prints the result.