Classroom Resource

Computer Science Principles Unit 3 Chapter 1 Lesson 5: Creating Functions

Subject Area

Digital Literacy and Computer Science

Grade(s)

9, 10, 11, 12

Overview

In this lesson, students learn to define and call procedures (in JavaScript, procedures are called “functions”) in order to create and give a name to a group of commands for easy and repeated use in their code. They will be introduced to functions as a form of abstraction that enables them to write code in larger, more logical chunks and focus on what something does, rather than how it does it. As they explore the use of functions through a sequence of activities in App Lab, they will be asked to think about where they see the need for functions and how these functions can make their code clearer or more concise.

At the end of the lesson, students review the concept of abstraction and are introduced to elements of the Create PT in preparation for the Practice PT at the end of the unit.

Students will be able to:
- recognize functions in programs as a form of abstraction.
- write a program that solves a turtle drawing problem using multiple levels of abstraction (i.e. functions that call other functions within your code).
- explain why and how functions can make code easier to read and maintain.
- define and call simple functions that solve turtle drawing tasks.

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Digital Literacy and Computer Science (2018) Grade(s): 09-12

DLCS18.HS.3

Differentiate between a generalized expression of an algorithm in pseudocode and its concrete implementation in a programming language.

Unpacked Content

UP:DLCS18.HS.3

Vocabulary

  • pseudocode
  • programming language
a.
  • approximated
b.
  • iteration
  • conditional statements
  • control structures
c.
  • iterative loop
  • selection constructs
  • recursion

Knowledge

Students know:
  • that differences exist in pseudocode and a programming language.
  • that programming languages have certain requirements for language and syntax.
a.
  • that some programs cannot return a result in a reasonable time frame, therefore approximations must be allowed in those cases.
b.
  • how to identify sequential statements, conditional statements, and/or iterations in code.
  • the differences between sequential statements, conditional statements, and/or iterations.
  • trade-offs exist with using one control structure over another.
c.
  • some decisions in a program will require the use of iterative loops, selection constructs, or recursion.
d.
  • programs can be written to satisfy a number of needs such as performance, reusability, and ease of implementation.
  • that most times, algorithms will differ based on the need of the program; performance, reusability, or ease of implementation.
e.
  • that programs can be written with specific priorities in mind.
  • that there are multiple correct ways to write a program.
  • that solutions are often chosen to meet the priority need of the program.

Skills

Students are able to:
  • distinguish between a generalized expression of an algorithm in pseudocode and its concrete implementation in a programming language.
  • point out similarities in vocabulary and syntax between pseudocode and an algorithm.
  • point out differences in vocabulary and syntax between pseudocode and an algorithm.
a.
  • explain that some algorithms do not lead to exact solutions in a reasonable amount of time and thus approximations are acceptable.
b.
  • identify sequential statements, conditional statements, and/or iterations in code.
  • identify tradeoffs associated with using one control structure over another.
c.
  • distinguish when a problem solution requires decisions to be made among alternatives or when a solution needs to be iteratively processed to arrive at a result.
d.
  • evaluate and select algorithms based on performance, reusability, and ease of implementation.
e.
  • explain how more than one algorithm may solve the same problem and yet be characterized with different priorities.

Understanding

Students understand that:
  • similarities and differences exist in pseudocode and programming code.
  • some programming languages more closely resemble pseudocode than do other programming languages.
a.
  • due to time or financial constraints, some programs may return an approximation of a solution.
b.
  • both benefits and drawbacks exist when selecting one control structure over another in a code.
c.
  • programs can use multiple methods to arrive at a solution.
d.
  • there are times when a program needs to be selected for a specific purpose, such as performance, reusability, and/or ease of implementation.
e.
  • multiple algorithms can solve the same problem.
  • algorithms can operate with a specific priority in mind, such as speed, simplicity, and/or safety.
Link to Resource
https://curriculum.code.org/csp-18/unit3/5/

CR Resource Type

Lesson/Unit Plan

Resource Provider

Code.org
Accessibility
License

License Type

Custom

Custom License Type (URL)

https://code.org/tos

Approved Date

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