3.1 Fundamentals of algorithms 3.1.1 Representing algorithms (Abstraction and decomposition) Lesson

TIME UP Starter activity In pairs… Start Person A explain the term abstraction to Person B. Person B explain the term decomposition to Person A. Between you write a definition of both. Compare with your neighbours and refine your definitions. TIME UP This timer bar takes 3 minutes and will turn purple when the time is up. Start

Objectives Understand how to apply abstraction to a problem. Be able to apply decomposition to a problem. Understand the link between decomposed problem parts and subroutines.

Using your choice of techniques, abstract this problem. Flash cards are a well-known tool for learning and revision. They normally consist of a piece of card with a keyword on one side and the definition of the keyword on the other side, for example: Keyword: Cellulose Definition: Tough substance that makes up the cell walls of green plants A teacher wants her students to use a computerised version of a flash card quiz to help them remember Key Stage 3 Biology definitions. The program should display a series of keywords to a student and ask them to choose the correct definition for each keyword. The quiz is completed once a student has matched each keyword with its definition twice. An external file containing the keywords and definitions to be used in the quiz will be provided by your teacher. Using your choice of techniques, abstract this problem.

Using your choice of technique, fully decompose this problem. Flash cards are a well-known tool for learning and revision. They normally consist of a piece of card with a keyword on one side and the definition of the keyword on the other side, for example: Keyword: Cellulose Definition: Tough substance that makes up the cell walls of green plants A teacher wants her students to use a computerised version of a flash card quiz to help them remember Key Stage 3 Biology definitions. The program should display a series of keywords to a student and ask them to choose the correct definition for each keyword. The quiz is completed once a student has matched each keyword with its definition twice. An external file containing the keywords and definitions to be used in the quiz will be provided by your teacher. Using your choice of technique, fully decompose this problem.

Model solution Have a look at the model solution. Is this enough? How does it compare to yours? The Model solution is included within the Lesson plan and printable activities Word document

Plenary Your key sections should correspond to subroutines within the code. Give each subroutine a suitable name. For each subroutine, identify what data it needs to complete its task. Identify where the data is coming from (other subroutines).