10. Exercise

• We want to develop a program that determines the future value of an investment, given the initial value and the interest rate

• We follow the steps for development.

• Analysis:

  • The initial money generates an annual interest rate

  • How much will it be worth in 10 years?

  • Input: initial amount, interest rate

  • Output: value in 10 years

• Specification:

  • The user enters the initial amount invested

  • The user enters the annual interest rate

  • Value of the financial mathematical formula * (1 + interest)

• Design:

  • Enter the initial investment amount.

  • Enter the interest rate.

  • Repeat 10 times:

    • initial value = initial value * (1 + interest rate)

  • Print the updated value.

• Implementation:

  • Test values:

    • 1000 dollars investment and 3% annual interest rate

    • 1000 dollars investment and 10% annual interest rate

value = float(input("Initial amount invested: ")) rate = float(input("Annual interest rate: ")) for i in range(10): value = value * (1 + rate / 100) print("Value after 10 years: %5.2f" % value)

10.1. FAQs

System Message: ERROR/3 (/home/runner/work/PyZombis/PyZombis/_sources/lectures/TWP40/TWP40_10_en.rst, line 44)

Duplicate ID – see lectures/TWP40/TWP40_10, line 48

.. mchoice:: feedback_l40_10_1
    :random:
    :answer_a: Helps us build the correct product without waste or redundancy
    :feedback_a: It often makes sense to write the test first and then write as much code as necessary to allow the test to pass.
    :answer_b: Makes the code run faster.
    :feedback_b: This is incorrect because defining tests doesn't directly affect the speed of the code.
    :answer_c: Allows the programmer to write less code.
    :feedback_c: This is incorrect because writing tests actually requires writing more code.
    :answer_d: Not necessary for good programming.
    :feedback_d: This is incorrect because defining tests is an important aspect of good programming practices.
    :correct: a

    Why is defining some tests before implementation a good programming practice?

System Message: ERROR/3 (/home/runner/work/PyZombis/PyZombis/_sources/lectures/TWP40/TWP40_10_en.rst, line 58)

Duplicate ID – see lectures/TWP40/TWP40_10, line 62

.. mchoice:: feedback_l40_10_2
    :random:
    :answer_a: Allows testing of the program's logical flow before coding it.
    :feedback_a: Writing pseudocode in the design stage provides several benefits, including the ability to test the logic and structure of the program before writing any actual code.
    :answer_b: Saves time and effort in later coding.
    :feedback_b: This is incorrect because writing pseudocode requires time and effort, but it's an investment that's worth it in the design stage.
    :answer_c: Helps identify syntax errors in the code.
    :feedback_c: This helps identify logical errors, gaps, and loopholes in the program design, which saves time and effort in the long run.
    :answer_d: Facilitates code debugging.
    :feedback_d: This helps identify logical errors, gaps, and loopholes in the program design, which saves time and effort in the long run.
    :correct: a

    What is the advantage of writing pseudocode in the design stage?

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