#-------------------------------------------------------------------------------
#  Function3.py
#  functions have return values
#-------------------------------------------------------------------------------

def sum_to(n):
   """returns sum of numbers from 1 to n """     # this is a doc string
   s = 0
   for x in range(1, n+1):
      s += x    # same as:  s = s+x
   return s
# end of function sum_to()

def fact(n):
   """returns product of numbers from 1 to n """ # another doc string
   p = 1
   for x in range(1, n+1):
      p *= x    # same as:  p = p*x
   return p     # try commenting out the return statement
# end of function fact()


#-- main program ---------------------------------------------------------------

for n in range(1, 41):
   print(n, '\t', sum_to(n), '\t', fact(n))

# print help on functions sum_to and fact, uses doc strings
help( sum_to )
help( fact )

# another way to print out doc strings
print( sum_to.__doc__ )
print( fact.__doc__ )