Python · Beginner level

Beginner level · Module 5: Python Beginner Project Studio · Lesson 1 of 3

Planning a Program from Requirements

Read a client-style requirement and break it into inputs, processing steps and outputs before coding.

In this lesson you will

  • Identify inputs, processing and outputs
  • Write pseudocode for each function

Key concepts

requirementsinput–process–outputpseudocode

The lesson

Professional programs start from requirements: what the user needs, what goes in, what comes out and what can go wrong. Writing this down before coding saves hours of rework.

Pseudocode is a plain-language outline of the steps, written so that anyone can follow it. For the Shop Sales Calculator it might read: ask for each sale until the user types done; add each amount; at the end show total, number of sales and largest sale.

List the inputs, outputs and edge cases — an empty day, a negative number, text instead of a number — and decide what the program should do for each. These become your test cases in the next lesson.

Step by step

  1. Write one sentence describing who will use the program and why.
  2. List inputs, outputs and edge cases in a table.
  3. Write pseudocode for the main flow.
  4. Name the functions you will build and get the plan approved.

Practice activity

Write the plan and pseudocode for the Shop Sales Calculator level project and have it approved by the instructor.

Expected result: An approved plan listing inputs, outputs and the functions to build.

Check your understanding

  1. What are the three parts of an input–process–output plan?

    Show answer

    What the program receives, what it does with the data, and what it produces.

Taught live by an instructor — online or in person. Free course lessons are for self-study and do not lead to a certificate — see registration options.