Unit2-02: Flowcharts & Constants

Learning Outcome

At the end of this lesson, you will be able to:

• A1.3 use assignment statements correctly with both arithmetic and string expressions in computer programs; 

• B1.1 use various problem-solving strategies (e.g., stepwise refinement, divide and conquer, working backwards, examples, extreme cases, tables and charts, trial and error) when solving different types of problems; 

• B2.4 represent the structure and components of a program using industry-standard programming tools (e.g., structure chart, flow chart, UML [Unified Modeling Language], data flow diagram, pseudocode); 

• B4.1 describe the phases (i.e., problem definition, analysis, design, writing code, testing, implementation, maintenance), milestones (e.g., date of completion of program specification), and products (e.g., specification, flow chart, program, documentation, bug reports) of a software development life cycle; 

• understand what a flowchart is and how to create one

• understand what a constant is and how to use one in Python & C++

Quiz Questions

With a pencil and paper, answer the following questions:

1. Declare a variable in Python that holds the total quantity of mass of a boomerang in a science experience. Set it to 339.5 grams. Then do the same for C++.

2. Declare a constant in Python called HST and set it to 0.13. Then do the same for C++.

3. Write the line of code in Python to ask the user to enter the subtotal cost of a t-shirt. Then do the same for C++.

4. Create the top-down design for a program that asks the user for the length and width of a soccer field and tells them the perimeter.

Lesson

• from the online book Computer Based Problem Solving by Patrick Coxall, read:

  • Flowcharts

  • Constants

• go over what a Flowchart is

  • different shapes have different meanings (see image on the right)

  • arrows always point down

  • normally left black and white

• create a flowchart for the "Area & Perimeter of a Rectangle with User Input"

  • watch "Create a Flowchart for the Area & Perimeter of a Rectangle"

  • use draw.io with a Blank Template

  • ALWAYS export it as a PNG file to maintain the resolution regardless of the size

    • File, Export As, PNG...

  • then insert the PNG into your Google Doc

  • ensure that you center, size and crop the image so that it fits nicely on the page

  • NEVER take a screenshot and paste it in as the resolution is not maintained

• go over what a constant is

  • uppercase with words separated by underscores as necessary to improve readability

  • constants will always be created in a separate module

    • go over how to create a module, it is just a separate python file

  • i.e. MONTHS_IN_YEAR = 12

  • i.e. SECONDS_IN_MINUTE = 60

  • i.e. HST = 0.13

  • i.e. BRAND = "Nike"

  • i.e. ALWAYS_ON = true

  • Note: 

    • in Python even when you declare a constant, someone could still change it

    • this is not true in all languages 

    • in C# and Swift, for example, if you declare a constant it can never be changed

    • to get around this we normally create a new python file (usually called constants.py) and place our constants in there and then "import" that file

How to Create a Flowchart for the Area & Perimeter of a Rectangle with User Input

Activity

• in groups of 2, do the following on the board for today's daily assignment:

  • Top-Down Design

  • Flow Chart

Daily Assignment

• complete the Daily Assignment section in Hãpara Workspace for this day

  • if Hãpara is not working, make a copy of this document

  • move it to your IMH-ICS folder for this course

Extra

• create the program from above in C++

  • note: constants in C++ are NOT declared in a separate file, they are declared above variables

  • i.e. const int LENGTH = 10;

  • i.e. const float MAX_VOL = 99.99;

  • i.e. const string PLANET = "Earth";

  • i.e. const bool ALWAYS_ON = true;