UTPA STEM/CBI Courses/Computer Science/Arrays

Course Title: Computer Science I

Lecture Topic: Arrays

Instructor: Christine Reilly

Institution: University of Texas - Pan American

Backwards Design

Course Objectives

• Primary Objectives- By the next class period students will be able to:
  • Identify cases where arrays are useful
  • Write C++ code to create an array
  • Write C++ code to access an array element

• Sub Objectives- The objectives will require that students be able to:
  • Understand how array elements are indexed
  • Have a good understanding of basic C++ programming

• Difficulties- Students may have difficulty:
  • Understanding how one variable can hold multiple values
  • Remembering the correct syntax for accessing elements of an array

• Real-World Contexts- There are many ways that students can use this material in the real-world, such as:
  • Games that use a series of data. Any game that uses a hand of cards or a series of dice. Board games such as checkers, chess, and Connect-Four can be represented using a two dimensional array.
  • Data management systems can be represented using arrays. Examples are the contents of a shopping cart and information about the employees of a company.

Model of Knowledge

• Concept Map
  • Analysis of problem, requires
    • Critical thinking skills
    • Summarizing skills
  • Design of solution (algorithm design), requires
    • Problem decomposition skills
    • Understanding of underlying programming concepts
      • Data types
      • Sequence
      • Control structures
      • Modular programming
      • Arrays -- this lesson
      • Abstract data types
      • Pointers
      • Data structures and algorithms
    • Use of design tools - pseudo code writing skills
  • Implementation of solution - tools of the trade
    • Learned in lectures through
      • Slides
      • Analogies
      • Simple programs
      • Group exercises
    • Using C++ to implement underlying concepts
    • Applying underlying concepts, covered in lectures using
      • In-class exercises
      • Lab assignments
      • Homework assignments

• Content Priorities
  • Enduring Understanding
    • Create an array
    • Initialize the array
    • Retrieve the value of a single element of the array
  • Important to Do and Know
    • How to iterate through an array
    • Change the value of an array element
  • Worth Being Familiar with
    • How to use a programming environment such as Visual C++

Assessment of Learning

• Formative Assessment
  • In Class (groups)
    • Working in groups to brainstorm an algorithm and write short segments of code to solve a small problem
    • Working in groups to trace a code fragment and determine the output of that code fragment
  • Homework (individual)
    • Programming project where the students use arrays to solve a given problem
    • Worksheet on basic array creation, initialization, and element access
• Summative Assessment
  • Exam
    • Code trace problems
    • Writing short fragments of code

Legacy Cycle

OBJECTIVE

By the next class period, students will be able to:

• Write C++ code to create and initialize arrays of any size
• Write C++ code to access an element within an array
• Write C++ code to iterate through an array

The objectives will require that students be able to:

• Understand basic C++ programming
• Understand how arrays are indexed

THE CHALLENGE

<Part 1> You are the programmer for MicroAir Airline. Every MicroAir airplane has 10 seats. You are given the task to write a program to manage the seat assignments on an airplane. The names of the passengers are stored in a file. The seats are numbered 1 through 10. Your program reads this file and assigns each passenger to a seat. The program needs to have a function to print the passenger list starting at seat 1 and going to seat 10, and another function to print the list starting at seat 10 and going to seat 1.

<Part 2> You have changed jobs and now work for JumboAir Airlines. Every JumboAir airplane has 200 seats. JumboAir also wants you to write a program that manages the seat assignments on an airplane. Can you make some small modifications and reuse the program you built while you were working at MicroAir?

GENERATE IDEAS

• Have the students work in groups on Part 1 of the challenge. Ask them to write an algorithm to solve the problem.
  • What is your approach to the problem?
  • What are the strengths and weaknesses of your approach?
• Add Part 2 of the challenge. Have the students go back to their groups.
  • Can the Part 1 solution work for Part 2?
  • What are the strengths and weaknesses of Part 1 applied to Part 2?
  • Are there changes to the solution to Part 1 that might make the program work better for Part 2? You don't need to know how to write a program for these solutions, just outline your ideas.

MULTIPLE PERSPECTIVES

• Discuss a sample of the students' solutions to Part 1 and Part 2.
  • Point out the strengths and weaknesses to the Part 1 solutions.
  • Discuss the ideas generated in Part 2.
• Lecture on Arrays. Focus on how we could build a good solution for Part 2 of the challenge question.
  • How to store people's names and their airplane seat.
  • How to access an element of the array.
  • How to iterate through the array to print each element.

RESEARCH & REVISE

• Students will work on exercises to practice simple problems using arrays.
• Have the students outline a solution for Part 2 of the challenge, using arrays.

TEST YOUR METTLE

• In-class exercises: students work individually or in small groups on code trace or short programming problems. We then discuss the solution, and try another similar problem.

GO PUBLIC

• Students will complete a programming assignment that requires them to use arrays to solve a complex problem.
• Students will take an exam where they have to answer questions about using arrays.

Pre-Lesson Quiz

1 An array can store many types of values

	TRUE
	FALSE

2 An array index starts with 1

	TRUE
	FALSE

3 The following is a proper declaration and initialization of an array

int arr[5] = {6, 9, 27, 76, 81};

	TRUE
	FALSE

Test Your Mettle Quiz

NOTE: The wiki code for this quiz has some errors

1 The following code will compile and run without errors:

int arr[10] = { 0 };
for( int i = 0; i <= 10; i++ )
{
   arr[i] = 1;
}

	TRUE
	FALSE

2 The output of the following code is:

int arr[5] = {5, 4, 3, 2, 1};

arr[1] = arr[4] + arr[1];
arr[3] = arr[3] + 1;

for( int i = 0; i < 5; i++ )
{
   cout << arr[i] << " ";
}

	5 4 3 3 1
	5 5 3 3 1
	8 4 3 4 5
	7 4 4 2 1