# This is the user input function
# Test file
# Matt Bishop, February 27, 2012
# ECS 10, Winter Quarter 2012

# function to read and vet user selection
# returns: n, the number of tosses
# NOTE: n must be positive; return -1 to quit
def getinput():
    # loop until we get good input
    while True:
        try:
            # get the input and check the type here
            n = int(input("n (EOF to quit): "))
        except EOFError:        # user wants to quit, so help her
            n = -1
            break
        except ValueError:      # user didn't enter a number
            print("You have to enter a positive n or EOF")
            continue
        # now check the value we read/were given
        if n > 0:
            break
        # this is bad, so say so
        print("You have to enter a positive n or EOF")

    # it's positve to continue, -1 to quit
    return n

# Main routine to enable us to test getinput()
def main():
    # get the input
    n = getinput()
    # loop until quit
    while n >= 0:
        # say what you got so user can check
        print("User entered", n)
        # get another input
        n = getinput()
    # all done! say what user typed
    print("Quitting: n =", n)

main()