Computer Science 111:

Introduction to Computer Science I

Gregory M. Kapfhammer

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Color Scheme

Key Concept

Corresponding Diagram

In-Class Discussion

In-Class Activity

Details in the Textbook

Objects and Primitives

Similarities and differences?

Can you create a list for both of these?

What does this look like in memory?

Aliases for reference variables

Refer to Section 3.1 for more details and diagrams!

String Manipulation

Real world examples of string processing?

Purpose of and ways to index a string?

See Figure 3.1 for the methods provided by String

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Let's Try It!

We can write a Java program to learn more about Strings

Input the program in Listing 3.1 on page 120

Can you explain the output of this program?

Now, change the replacement and the substring!

Work on this programming task with your partner

If you create and fix an error, post the details in Slack!


What is a class library?

Application programming interface (API)

What are some examples of packages?

Check the online documentation!

Make sure to use an import!

Let's explore a new package!

Random Numbers

Provided by java.util.Random

Calculations based on a seed value

Input, compile, and run the program in Listing 3.2

Just one of the nextInt and nextFloat calls

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Formatting Output

What do you do if the output needs a special format?

The DecimalFormat and NumberFormat classes

You can format correct for currency and percentages!

See details in the text — may help on an assignment!

Enumerated Types

What to do if a variable only has a few possible "types"?

For instance, a letter grade has distinct values

Or, across the world, seasons have categories

You can use enumerated types to define these categories

See details in the text — may help on an assignment!