euler/python/e020.py

"""Find the sum of digits in 100!

n! means n  (n  1)  ...  3  2  1
Find the sum of the digits in the number 100!
"""

# Could use math.factorial, but that takes the fun out of it, doesn it
def factorial(n):
    f = n
    i = n - 1
    while i > 1:
        f = f * i
        i = i - 1
    return f

def main():
    f = str(factorial(100))
    sum = 0
    for c in f:
        sum = sum + int(c)
    
    print 'Sum of digits in 100!:', sum

if __name__ == '__main__':
    main()