M4) Does It Run?

Consider the Python code snippets in Listing 1. Each snippet attempts to generate a random floating-point number between a lower bound (inclusive) and an upper bound (exclusive).

Listing 1: Code snippets to generate a random number between a lower bound (inclusive) and an upper bound (exclusive) in Python. Which of them will run? (Question 1).

(a)

from random import random


def random_number_between(lower_bound, upper_bound)
    difference = upper_bound - lower_bound
    return difference * random() + lower_bound


def test():
    print(random_number_between(1, 10))


test()

(b)

from random import random


def random_number_between(lower_bound, upper_bound):
    return (upper_bound - lower_bound) * random() + lower_bound


def test():
    print(random_number_between(lower_bound, upper_bound))


test()

(c)

from random import random


def random_number_between(lower_bound, upper_bound):
    return (upper_bound - lower_bound) * random() + lower_bound


def test():
    print(random_number_between(1, 10))


test()

(d)

from random import random


def random_number_between(lower_bound, upper_bound):
    difference = upper_bound - lower_bound
    return difference * random() + lower_bound


def test():
    lower_bound = 1
    upper_bound = 10
    result = random_number_between(lower_bound, upper_bound)
    print(result)


test()

Which of the code snippets in Listing 1 will run without errors when executed?

1. Listing 1 (a) and Listing 1 (b)
2. Listing 1 (b) and Listing 1 (c)
3. Listing 1 (c) and Listing 1 (d)
4. Listing 1 (d) and Listing 1 (a)

Tip

Pay attention to the colon after each def header, the return statement, and whether every name used in test has been defined.

TipFunctions Used in the Python Code Snippets

• random: function from Python’s random module that returns a floating-point number in the interval \([0, 1)\).
• print: built-in function that displays a value.
• def: keyword used to define a function.
• return: statement that sends a value back to the function caller.