ap csa assignment 2 control tower

AP Computer Science Assignments

Learn Java Programming Supplemental, free, online textbook called Introduction to Programming Using Java Java Cheat Sheet Classes, Objects, & Constructors AP Quick Reference Guide Online Java Compiler Java Examples Arithmetic Operators Digital Textbook Visualize Java code execution Apr 16 We move on with Unit 5: Lesson 7 - Fast Start . This lesson we are going to review how to document a class in Java using comments. This lesson explains how comments can be used to describe the functioning of a class. There will be review questions and coding exercises. Apr 15 We continue with Unit 5: Lesson 6 - Fast Start . Last lesson we learned some of the basics about creating classes. Today we will learn more details about writing constructors for classes. This lesson examines constructors more closely and how to use overloading to enable multiple constructors. There will be review questions and coding exercises. Apr 12 Today we will finish the Unit 5: Lesson 5 - Coding Activities . Apr 11 We start today with the Unit 5 Quiz . The access code sandwich . Then, we continue with Unit 5: Lesson 5 - Fast Start .Now that you have practiced using object data types, you are ready to learn how to create your own objects! This lesson covers the basics of creating our own classes from scratch. There will be review questions and coding exercises. Apr 10 Today we'll finish the Unit 5: Lesson 4 - Coding Activities . Apr 9 We continue with Unit 5: Lesson 4 - Fast Start . In the last lesson we learned how to pass parameters to a method. Now we are going to learn how to return values from a method. There will be review questions and coding exercises. Apr 8 Next is Unit 5: Lesson 3 - Fast Start . In the last lesson, we learned how to add parameters to the methods that we write. Today we are going to explore some of the challenges of working with parameters. By the end of today, you will know some of the differences between primitive vs. class parameters. This lesson explores some of the challenges of working with parameters, and the differences between primitive vs. class parameters. There will be review questions and coding exercises. Mar 29 Today we're going to try to catch up on the Unit 5: Lesson 2 - Coding Activities from yesterday. Mar 28 We continue with Unit 5: Lesson 2 - Fast Start . In the last lesson, we learned how to create methods. In this lesson, we are going to learn how to add parameters to a method. There will be review questions and coding exercises. Mar 27 We begin Unit 5 with Unit 5: Lesson 1 - Fast Start . We've learned already how to call methods of all types. We've written one method ourselves too in every program we've created: the main method. In this lesson we're going to be looking at how to write more methods. This lesson explains void methods, methods that don’t have a return statement. This lesson introduces parameters, which are input for methods. There will be review questions and coding exercises. Mar 26 We finish Unit 4 with Unit 4 Exam . The access code toothbrush. Use the Online Java Compiler to check the code in questions 1, 2, 3, 8, 10, 11, 12, 13, 14, 15, 16, 17, 19, & 20. After that we will go over the remaining questions together. For number 2, add this line to the beginning of the code String str = ("africa"); For number 19, add this line at the end of the code System.out.println(result); Mar 25 Let's use today to finish with Assignment 4: String Shortener . Mar 22 We continue with Unit 4: Lesson 6 - Fast Start . In this unit we've been hearing lots about algorithms. Today we'll look a little deeper at how we measure the efficiency of an algorithm. This lesson introduces the concept of algorithmic efficiency. Then we will do Assignment 4: String Shortener Mar 21 We continue with Unit 4: Lesson 5 - Fast Start . We've been using loops for some time now. In this lesson we advance a level and see what happens when we put a loop inside a loop. This lesson introduces the use of nested loops: loops inside other loops. There will be review questions and coding exercises. Mar 20 Let's finish the Unit 4: Lesson 4 - Coding Activities . Mar 19 We start with Unit 4: Lesson 4 - Fast Start . Last time we learned about the for loop. Today we are going to learn how to create algorithms which use a for loop to traverse the characters in a String. In this lesson, you will learn how to apply algorithms which use string traversals. There will be review questions and coding exercises. Mar 18 Sign in to your online accounts Go to Project STEM sign up with your school email account. Next go to Course Overview. This course focuses on the details of writing computer software using the Java programming language. Our goal is to stress an object-oriented perspective throughout the material. The course emphasizes basic ideas of software engineering and our goal of developing high-quality software. We will also look at and discuss social and ethical issues around computing throughout the year. The course will consist of code-along lessons, daily programming exercises, longer coding assignments, and regular quizzes and exams. Each lesson includes practice exercises including shorter coding problems. Well over 20 hours of instructional time is spent in hands-on coding. Click here for the course syllabus. Returning students go to Java Exercises Mar 13 We start with Unit 4 Quiz . The access code is penguin. Mar 12 We continue with Unit 4: Lesson 3 - Fast Start . In the first part of this unit we learned how to write a while loop and use this to create algorithms . Today we will learn a new way to repeat commands: the for loop. There will be review questions and coding exercises. Mar 11 Today we will finish Unit 4: Lesson 2 - Coding Activities . Mar 8 We continue with Unit 4: Lesson 2 - Fast Start . Recently we learned about controlling our programs with conditionals and loops. Today we are going to learn how to combine these to create algorithms which allow us to compute information about numbers. This lesson introduces the concept of algorithms, and how to create algorithms that use while loops and flag variables. There will be review questions and coding exercises. Mar 7 We begin unit 4 with Unit 4: Lesson 1 - Fast Start . In the last unit we learned a lot about conditional logic with: if statements, else statements, boolean operators, short circuit evaluation and DeMorgan’s Law. Today we are going to start applying these conditionals to a new control statement: the while loop. The while loop allows us to repeat blocks of code as long as a condition is true. It is the first step towards writing programs that can process immense amounts of input or data with complex algorithms, using only a few lines of code. This lesson introduces loops, which are used to repeat commands. While loops allow us to repeat blocks of code as long as a condition is true. There will be review questions and coding exercises. Your browser does not support the video tag. Mar 5 Today we will take the Unit 3 Exam . The access code is elephant . When you are done, you may check to see if you are missing any other work. Mar 4 Today we will do Assignment 3: Crack the Code! . In this assignment, you will be creating a program that requires a secret code to “unlock.” The program should first welcome the user and ask the user to input their name. Then, the program will greet the user using the entered name and ask whether they are ready to crack the code. If they type "yes" (using any combination of upper/lower-case letters) then the program should proceed to the next stage. Otherwise, it should finish at that point and produce no more output. This assignment is worth 10 points, so if you don't get a score you are happy with, keep working because this one does not get rounded up. Mar 1 We finish the week with Unit 3: Lesson 7 - Fast Start . Previously in this unit we learned how to check whether two primitive values are equal by using the comparison operator ==. Today we will learn how to determine whether two objects (i.e. class data variables) are equal or not. This lesson discusses how to compare the values of class-type data in if statements. There will be review questions and coding exercises. Feb 29 We continue with Unit 3: Lesson 6 - Fast Start . Last time we learned how Java uses short circuit evaluation to do compound logical statements. Today we are going to learn more about understanding compound logical statements with De Morgan’s Law. While short circuit evaluation is a rule about how Java evaluates boolean expressions, De Morgan's Law is a general mathematical law that can be used to simplify logical expressions independent of Java programming. This lesson introduces De Morgan’s Law, which is used to simplify boolean statements. It can be a very powerful tool when simplifying or evaluating logical expressions. There will be review questions and coding exercises. Feb 27 Next, we move on to Unit 3: Lesson 5 - Fast Start . Last time we learned how we can use boolean variables and operators to construct complex logic expressions. Today we are going to learn how to understand a rule called short circuit evaluation, which applies to compound boolean statements, where multiple values are combined with operators into larger expressions. This lesson introduces short-circuit evaluation, which is a shortcut for evaluating boolean statements. There will be review questions and coding exercises. Feb 26 Today we will take the Unit 3 Quiz . The access code is macaroni . Then we move on to Unit 3: Lesson 4 - Fast Start . Last time we learned how we can use an else statement to add multiple options to if statements. Today we are going to learn something new, boolean values. Boolean values are a very important logical concept which will allow us to set values to either true or false. Boolean values are the result of comparisons (like ==) and can be used as the conditions of if statements or, with boolean operators, to construct more complex logical statements. There will be review questions and coding exercises. Feb 23 We move on to Unit 3: Lesson 3 - Fast Start . In the last two lessons, we learned about if statements and the basic comparison operations that they can support. In this lesson, we are going to learn about else statements, a tool that can make if statements even more powerful. This lesson introduces else statements, which allow code to be executed when an if statement is false. There will be review questions and coding exercises. Feb 22 We continue with Unit 3: Lesson 2 - Fast Start . Last time we learned the basics if statements, which act like gates in our code. Today we will be learning about more things that we can do with if statements, replacing the == operator with different kinds of comparisons. This lesson introduces additional value operators in if statements. There will be review questions and coding exercises. Feb 21 Today we will finish Unit 3: Lesson 1 - Coding Activities . Feb 20 Today we will take the Unit 2 Exam . The access code is sailboat . Next is Unit 3: Lesson 1 - Fast Start . Today we are starting a new unit: Boolean Expressions and If Statements. Units 1 and 2 covered the basics of programming in Java, including input, output, variables, Strings and number calculations. In Unit 3, we are going to learn how to write programs with different branches for different circumstances. We do this using conditional statements; so called because they allow us to control which commands our program will run depending on different conditions. There will be review questions and coding exercises. Feb 14 Today we will do Assignment 2: Control Tower . In this assignment, you will be simulating an Air Traffic Control tower. This program uses data of the Airplane class type. This is a custom class that you will use for this activity. This assignment is worth 10 points, so if you don't get a score you are happy with, keep working because this one does not get rounded up. Feb 13 Next is Unit 2: Lesson 8 - Fast Start . In this unit we have learned to use classes and objects, including calling methods. Today we are going to see a new class, the Math class, which has a load of useful methods to help us do calculations with numbers in Java. In this lesson, you will be introduced to Java’s math package and learn about static methods. There will be review questions and coding exercises. Feb 9 There are no new assignments today. Check to see that you have everything we covered during this term. After today, you may not make up any of these. We started with Unit 1, Lesson 1 We finished with Unit 2, Lesson 7 We also did Quiz 1 Exam 1 Assignment 1 Quiz 2 Beginning next term, you will be working on the review questions, quizes, and exams on your own. You may choose to work with a classmate. Feb 8 We will start with Unit 2: Lesson 7 - Fast Start . We have now encountered several different class data types. In this lesson we will look at wrapper classes, which allow us to use primitive data types as objects. In this lesson, you will learn about wrapper classes, and about the processes of autoboxing and unboxing. There will be review questions and coding exercises. Feb 7 Now we will continue with Unit 2: Lesson 6 - Fast Start . Last lesson we introduced the shapes classes to allow us to practice using constructors. This lesson we will look at the methods available to objects of these classes and take a closer look at how methods in general work for a class. This lesson introduces more theory and examples of methods in Java, using the shapes classes for examples. There will be review questions and coding exercises. U2_L6_template Feb 6 We will take the Unit 2 Quiz . The access code is pineapple. Then we will continue with Unit 2: Lesson 5 - Fast Start . Over the last few lessons we have been learning about classes and objects, primarily focusing on the String class. In this lesson we will be looking at how we can introduce new classes to Java, and then instantiate objects of those class types. In this lesson, you will be introduced to constructors, which are used to create objects in Java. There will be review questions and coding exercises. This is the code for the lesson-- Shapes Constructors Feb 5 We start with Unit 2: Lesson 4 - Fast Start .In the first few lessons of this unit, we learned what a class data type was. Now we will explore in greater depth what we mean by a "class" and an "object". This lesson explains the class-object structure found in Java (and other object-oriented programming languages). There will be review questions and coding exercises. Type this into the compiler Feb 2 We end the week with Unit 2: Lesson 3 - Fast Start .In the last 2 lessons we learned more about the String class. Today we are going to learn about some of the functions in that class. In this lesson, you will learn about some methods in the String class. There will be review questions and coding exercises. Feb 1 We end the week with Unit 2: Lesson 2 - Fast Start . Today we are going to get more sophisticated with Strings and how they are displayed. This lesson explores how to have more control over text output with escape sequences, and outlines some things to be aware of when concatenating Strings with numbers. There will be review questions and coding exercises. Jan 31 We move on to Unit 2: Lesson 1 - Fast Start . Today we are starting a new unit: Using Objects. We are going to begin by learning more about Strings and the differences between primitive and class data types. There will be review questions and coding exercises. Jan 30 Today we will take the Unit 1 Exam . The access code is fireplace . This is the code in the lesson. Jan 29 Today we do Assignment 1: Calculating Grades . For this assignment, you will write a program to calculate a student's final course grade based on the student's homework, quiz, and final exam scores. The first input to the program will be the name of the course (as a string), followed by the average amount of time the student spent on the course per week in minutes (as an int). Then, the program will then read 4 integers representing the student's homework scores, 2 decimals representing the student's quiz scores, and finally, a decimal representing the student's final exam score. The program should then output the course name and the average time spent for the course in a week in hours and minutes. This should be followed by the average homework grade, the average quiz grade, and the final exam grade (as doubles), and an overall grade (as an int). Jan 25 Next is Unit 1: Lesson 6 - Fast Start . In the last two lessons, we learned how to do calculations with numbers, including division with integers. In this lesson, we are going to learn how to switch between double and integer data types when we need to. There will be review questions and coding exercises. Jan 24 Next up is Unit 1: Lesson 5 - Fast Start . By the end of this lesson, you will learn modular division, also known as remainder division, a type of division that is fundamental to various Java applications. There will be review questions and coding exercises. Jan 23 Go to this link regarding interest in a guitar class. We pick up with Unit 1: Lesson 4 - Fast Start . Then we move on to the lesson, Unit 1: Lesson 4 - Number Calculations. In this lesson, you will learn about arithmetic calculations in Java. There will be review questions and coding exercises. Jan 22 Today we will explore Java in a more hands-on way. We will compile and run files manually. Running your Java programs from the command line gives an appreciation to the entire compilation and execution process that happens when executing your Java programs. We’ll start off by running a single Java file but first, let’s create that file. To create a single Java file, all that is needed is the name of the file plus the .java extension. Start by opening TextEdit and type in the code below. Save as DemoTerminal.java in the java folder. Now open the terminal and type cd java Then type javac DemoTerminal.java It should return a line like the one above it. If it does type java DemoTerminal If it runs successfully, the program will execute Running in terminal. Now we'll try some other, more interesting programs. Jan 19 We will finish Unit 1: Lesson 3 - Coding Activities . There are 3 activities, and then we'll spend the last 15 minutes doing the Unit 1 Quiz . The access code is truffle. Jan 18 We continue week with Unit 1: Lesson 3 - Fast Start . In the last lesson, we saw that we can store user input in variables. In this lesson, we will spend more time with variables, learning how we can store numbers instead of Strings. Then we'll move right into Unit 1: Lesson 3 - Data Types. There will be review questions and coding exercises. Jan 17 Today we'll move on to Unit 1: Lesson 2 - Fast Start . In this lesson, we will learn how to get input from the user. Also, we will see that by storing this input in variables we can start to write much more useful programs. There will review questions and coding exercises. Jan 16 Sign in to your online accounts Go to Project STEM sign up with your school email account. Next go to Course Overview. This course focuses on the details of writing computer software using the Java programming language. Our goal is to stress an object-oriented perspective throughout the material. The course emphasizes basic ideas of software engineering and our goal of developing high-quality software. We will also look at and discuss social and ethical issues around computing throughout the year. The course will consist of code-along lessons, daily programming exercises, longer coding assignments, and regular quizzes and exams. Each lesson includes practice exercises including shorter coding problems. Well over 20 hours of instructional time is spent in hands-on coding. Today we will jump right into the assignments, starting with Unit 1: Lesson 1 - Output in Java . In this lesson, you will get acquainted with your programming environment and write your first lines of code in Java. Each lesson includes practice exercises including shorter coding problems. Well over 20 hours of instructional time is spent in hands-on coding. Jan 11 We are going to design a way to graphically represent data from a recent studedy on the workplace. The study sought to find ot if people would rather work at hohme or in the office. Here are the question that they posed-- During your typical work week, where do you spend your time working? (fill in pie chart as % of week) How much time do you ideally need to spend at your company’s office to maximize your individual and team’s productivity? (fill in pie chart as % of week) What year were you born? (fill in year) Students can segment by age brackets as well as generations if desired. What is your living situation? (multiple choice answers: live alone, with others, older or younger children, etc) What is the length of your commute each way? (multiple choice answers) Jan 10 One more day to practice coding for a couple of days. Copy these 2 programs (one at a time) in the Online Java Compiler . Run them and see what happens. Jan 9 We are going to practice coding for a couple of days. Copy these 2 programs (one at a time) in the Online Java Compiler . Run them and see what happens. Jan 8 Sign in to your online accounts Go to Project STEM sign up with your school email account. Go to Java Exercises I also want you to create a document in your Google drive named Java Vocabulary. From time to time I'll ask you to add to it. Next go to Course Overview. This course focuses on the details of writing computer software using the Java programming language. Our goal is to stress an object-oriented perspective throughout the material. The course emphasizes basic ideas of software engineering and our goal of developing high-quality software. We will also look at and discuss social and ethical issues around computing throughout the year. The course will consist of code-along lessons, daily programming exercises, longer coding assignments, and regular quizzes and exams. Each lesson includes practice exercises including shorter coding problems. Well over 20 hours of instructional time is spent in hands-on coding. Click here for the course syllabus. This work is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License .

# Unit 2: Using Objects

# lesson 1: strings and class types, # lesson 2: escape sequences and string concatenation, # lesson 3: string methods, # lesson 4: classes and objects, # lesson 5: using constructors, # lesson 6: using methods, # lesson 7: wrapper classes, # lesson 8: math functions, # assignment 2: control tower.

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5.2 Constructors

3 min read • december 28, 2022

Athena_Codes

The Student Class

Let's start writing our classes by declaring our instance variables and class headers for the Student class :

Now, we need to make our constructor for the Student class . The constructor will need to initialize all the above instance variables and allow the client to have the opportunity to set some of the variables to values of their own choosing. For this, we are allowing gradeLevel, name, and age to be set. These will be our constructor parameters with initial values .

An object’s state refers to its attributes and their values at a given time; the state is defined by instance variables belonging to the object. Constructors are used to set the initial state of an object, which should include initial values for all instance variables .

We will first make the full constructor below and then write the overloaded constructors in Topic 5.9.

When a constructor is called, the parameters are local variables , which means that the variables are only defined inside that constructor . Notice how the parameter names are different than the names of the instance variables . In Topic 5.9 we will learn how to keep both as the same name which is the conventional way to do it.

If one of the parameters for the constructor is a mutable object (meaning that its state can be changed after it has already been created), the instance variable should be initialized with a copy of the object referenced in the parameter. This keeps us from accidentally changing the state of the original object.

Before we move on to the constructor for the Assignment class , if we don't include a constructor for a class , and we try to make a new object, Java will automatically create a default constructor with default values set for the instance variables . Here is a list of them for certain data types:

Default Values by Data Type

The assignment class.

With that, let's do the same with the Assignment class .

To see how constructors are used to create instances of a class , you can visit Topic 2.2 !

Key Terms to Review ( 10 )

Constructor

Instance Variables

Key Term: String

Mutable Object

Object's State

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