Programming Fundamentals/Arrays/Fixed-Length Arrays

A fixed-length array is an array for which the size or length is determined when the array is created and/or allocated. This activity introduces fixed-length arrays. This activity will help you understand how to use fixed-length arrays in a program.

Objectives

• Understand fixed-length array concepts
• Understand how fixed-length array values are assigned in a program.
• Use a for loop to assign and display array values.

Prerequisites

Learners should already be familiar with defined-value arrays and the syntax for defining fixed-length arrays in their preferred programming language.

Introduction

Review the following pseudocode.

Declare Integer values[3]

For index = 0 To 2
    Output "Enter value " + (index + 1) + ":"
    Input values[index]
End For

For index = 0 To 2
    Output values[index]
End For

Questions

• What syntax is used to define fixed-length arrays in your preferred programming language?
• What syntax is used to reference array elements in your preferred programming language?
• What syntax is used to assign a value to an array element in your preferred programming language?
• What number is used to reference the first element in an array?

Activity

With a partner, use Repl.it or your preferred integrated development environment (IDE) to create a program based on the pseudocode above.

1. Start by declaring an array with a fixed length of three.
2. Create a for loop to input values into the array.
3. Create a for loop to display the array values.
4. Save the program.
5. Test the program to verify that it works correctly.
6. Trade places, so that both partners have an opportunity to "drive" the programming environment.
7. Modify the program to increase the number of values in the array.
8. Modify the program to decrease the number of values in the array.
9. Experiment with using the wrong starting or ending index values in the for loop (For example, 1 to 3 rather than 0 to 2).
10. Working together, create a list of changes that might be made to use fixed-length arrays in programs you've already written. What parts could be replaced with a fixed-length array?

Applications

• Identify specific steps which must be followed when creating a program using fixed-length arrays.
• Discuss your activity experience with your classmates. What surprised you? What have you learned that you can apply to your own school or work environment?