nt "Enter x value or blank line: "
            x = readline.chomp
            break if x == ''
            raise EOFError.new if x == 'quit'

            # If it looks bad, let's try again.
            if x !~ /^\-?\d+$/
                print "That doesn't look like an integer.  Please try again.\n"
                next
            end

            # Convert to an integer and print the result.
            x = x.to_i
            print "p(x) = ", polystr(poly), "\n"
            print "p(", x, ") = ", polyval(