# Program to read in a positive number
# and complain when the input isn't that
# Matt Bishop, February 23, 2012
# ECS 10, Winter 2012

# read in a positive number
# raise a ValueError if input is 
def getposnumber():
    # read the input and convert it to an integer
    # notice we do *not* catch the error here; it
    # is to be caufht by the caller
    instr = input("type a number: ")
    n = int(instr)
    #
    # okay, it's an int -- f it's a nonpositive one, complain
    #
    if n < 0:
        raise ValueError("You entered a negative number")
    elif n == 0:
        raise ValueError("You entered 0")
    #
    # now just return it
    #
    return n

#
# the program itself
#
def main():
    #
    # loop to show how to break out of an infinite loop
    #    
    while True:
        #
        # read in a positive nteger
        # handle any exceptions (relatively) intelligently
        #
        try:
            n = getposnumber()
        # first exception: bad value (string, invalid number)
        except ValueError as msg:
            print(msg)
            print("You need to enter a positive number")
        # next exception: user typed EOF, so leave loop
        except EOFError as msg:
            print(msg, "-- bye!")   # say bye!
            break
        # no exception -- print the number
        else:
            print("Read", n)
        finally:
            print("\n-----------------------\n")

main()