Arizona State University CSE110 – Lab #6

Coding Guidelines
• Give identi?ers semantic meaning and make them easy to read (examples numStudents, grossPay, etc).
• Keep identi?ers to a reasonably short length.
• Use upper case for constants. Use title case (?rst letter is upper case) for classes. Use lower case with
uppercase word separators for all other identi?ers (variables, methods, objects).
• Use tabs or spaces to indent code within blocks (code surrounded by braces). This includes classes,
methods, and code associated with ifs, switches and loops. Be consistent with the number of spaces or
tabs that you use to indent.
• Use white space to make your program more readable.
• Use comments after the ending brace of classes, methods, and blocks to identify to which block it
belongs.

Assignment/Lab Documentation
At the beginning of each programming assignment you must have a comment block with the following
information:
/*————————————————————————// AUTHOR: your name
// FILENAME: title of the source file
// SPECIFICATION: description of the program
// FOR: CSE 110- Lab #6
// TIME SPENT: how long it took you to complete the assignment
//———————————————————–*/

References
• (Page 362) Writing classes
• (Page 371) Instance variables
• (Page 372) Writing methods inside the class
• (Page 375) Constructors
• (Page 380) Testing a class

1

Getting Started
Create a class called Lab6 and a class called SuperHero. Be sure to import the Scanner class in Lab6. Be
sure to name your ?les Lab6.java and SuperHero.java, respectively. Also, make sure the ?les are saved in
the same directory.

Task Overview
Remember that creating by creating a class, we are de?ning a Java Object. These objects are often used to
model various real-world objects. The overall goal of this lab is to create a class to model a superhero. This
SuperHero class will then be tested using the Lab6 driver class.

Part 1: De?ning the Class
The ?rst part of creating any class is to declare it as a class. The overall set up for the SuperHero class
when the lab is done should look something like the code below. Copy it to your SuperHero.java ?le.
public class SuperHero {
// instance variables go below here
// the two constructors go below here
// getNumberOfHeroes() goes below here
// recordSave() goes below here
// the second recordSave method goes here
// killHero() goes below here
// printSuperHeroRecord() goes below here
}

Part 2: De?ning the Instance Variables
Instance variables are used to de?ne di?erent traits about an object. In the SuperHero class, de?ne the
following instance variables in the appropriate place:
• numberOfHeroes, a static int
• heroName, a String
• secretIdentity, a String
• numberOfLifeChances, an int
• numberOfPeopleSaved, an int

Notes & Hints
• Be sure to declare all of your instance variables as private, as we do not want other programs to have
direct access to them.
• numberOfHeroes needs to be a static variable, because its value needs to be the same between all
instances of the SuperHero class. You can read about static instance variables on page 400 or see
the video example.
2

• As an example for the other three, the heroName instance variable is written below:
private String heroName;
The section on instance variables starts on page 371.

Part 3: Creating the Constructors
The purpose of a constructor is to de?ne the instance variables of the object upon its creation. By allowing for
arguments to be passed into the constructor, these instance variables can be easily customized. For example,
the following constructor will allow for the heroName, secretIdentity, and numberOfPeopleSaved to be
customized:
public SuperHero(String initHeroName, String initSecretIdentity, int initPeopleSaved) {
numberOfHeroes++; // one more hero created
numberOfLifeChances = 2; // start the hero with two lives
heroName = initHeroName;
secretIdentity = initSecretIdentity;
numberOfPeopleSaved = initPeopleSaved;
}
Include this code in the constructor section of your SuperHero class. Notice how numberOfHeroes and
numberOfLifeChances are explicitly de?ned in the constructor, while the values of the other instance variables depend on what was passed into the constructor.
Now, create another constructor that will only take one parameter for the hero’s name. The constructor
should contain the following (you can place it below the ?rst one):
• Only allow the heroName as a parameter for the constructor
• Use the same code for de?ning the numberOfHeroes and the numberOfLifeChances
• Set the heroName attribute to the parameter passed into the constructor
• Set the secretIdentity to "unknown"
• Set numberOfPeopleSaved to 0
When this part is completed, you will have a SuperHero class with two constructors. The following calls
will be valid calls to one of the constructors:
SuperHero hero1 = new SuperHero("Superman", "Clark", 1000);
SuperHero hero2 = new SuperHero("Batman");
The section on constructors start on page 375.

Part 4: Creating the Other Methods
Now that we have the instance variables and constructors made, we need to de?ne some other methods to
make the class useful.

Method: getNumberOfHeroes
First, we will create an accessor method to return the number of heroes. To do this, simply ?ll in the body
of this method:
public static int getNumberOfHeroes() {
// Put something here (only 1 line is required)
}
3

Method: recordSave
Next, we will create a method to keep track of when the hero saves someone. This method will simply
increment the numberOfPeopleSaved instance variable by 1. This method is given to you below. Include it
in your lab.
public void recordSave() {
numberOfPeopleSaved++;
}
Now, create another method called recordSave. This time, require an integer, called num, as input. Inside
of the method, increment the number of people saved by this value. This allows a hero to save multiple
people at once. An un?nished version of this is given below:
public void recordSave(<define a parameter, "int num", here>) {
// Increment numberOfPeopleSaved by num
}

Method: killHero
If a hero is defeated by his/her enemy, they should lose a life. This is represented by decreasing numberOfLifeChances
by 1. However, the hero cannot possibly die if they have no lives. So, if the hero has no lives left, display a
message stating as such. The code is partially given to you below:
public void killHero() {
if (<check if the hero has lives, using numberOfLifeChances>) {
// Decrease numberOfLifeChances by 1
} else {
// Print a message saying the hero is dead
}
}

Method: printSuperHeroRecord
This method will simply print out the di?erent attributes of the hero. The output should look like the
following:
Name: Superman
Secret Identity: Clark
Status: Alive
People Saved: 1000
Note that if the hero has no lives left, the status should be ”Dead”.
Hints for this method
• Use what you know about printing messages and variables – use the instance variables where appropriate
inside of your print statements.
• You can use the same logic as the killHero() method to detect whether the hero is alive. Thus, you
will need to use an if-else statement inside of this class.
• Since you will be printing all relevant output to the console, you do need to return anything.
The section on writing methods in classes starts on page 372.

4

Part 5: Create a Test SuperHero
Now that we have the SuperHero class created, we need to make a class to test it. This is the Lab6.java
?le, as explained in the Getting Started section. Make sure you’ve imported the Scanner class. All of the
following instructions should be implemented inside of the main method of the Lab6 class. Copy the following
code into your Lab6 main method. We will be modifying this code.
// Create a Scanner object for later use
Scanner scan = new Scanner(System.in);
// Create a superhero called Spider-Man
System.out.println("Creating Spider-Man…….");
SuperHero spiderman = new SuperHero("Spider-Man");
// Ask the user to enter a superhero name
System.out.println("\nWhat is your super hero’s name?");
String heroName = scan.nextLine(); // This is line 10
System.out.println("What is his secret identity?");
/** 13: Read in the identity */
System.out.println("Creating your super hero…….");
/** 16: Create the hero called yourHero, who saved 10 people */
System.out.println("\nSpider-Man just saved 100 lives!");
/** 19: Call recordSave on spiderman with 100 as the input */
System.out.println("Oops, Spider-Man was shot dead twice!");
/** 22: Kill spiderman twice */
System.out.print("\nYour hero saved a kidnapped kid ");
System.out.println("but was shot once");
/** 26: Kill your hero once */
/** 27: Add 1 to your hero’s lives saved */
System.out.println("\n—- Superhero information —-");
/** 30: Store the number of heroes in an int called numHeroes */
System.out.println("There are " + numHeroes + " known superheroes.");
spiderman.printSuperHeroRecord();
System.out.println();
/** 33: print the record of yourHero */
Replace the "/**<comment>*" comments with the appropriate code. Each of these comments contains its
line number for reference in the below hints.
Hints
• Line 13: This is very similar to what was done on line 10, just with a di?erent variable name.
• Line 16: You will be using the constructor given to you in the lab. Use the the variables from lines 10
and 13 as the name and identity and the value 10 for the numberOfPeopleSaved.
• Line 19: For example, spiderman.recordSave() will call the recordSave() method for one person.
• Line 22: Simply call the killHero() method twice on the spiderman object.
• Line 26: Simply call the killHero() method once on your hero object.
• Line 27: Simply call the recordSave() method once on your hero object.
• Line 30: You will need to use the getNumberOfHeroes() method with the class name, like:
SuperHero.getNumberOfHeroes()
and store the returned value in the numHeroes variable you have to create.

5

• Line 33: Call the appropriate method of your hero object, similar to as done above for the spiderman
object.
The section on testing classes starts on page 380.

Sample Output
Below is an example of what your output should roughly look like when this lab is completed. All text in
bold represents user input.
Sample Run:
What is your super hero’s name?
Superman
What is his secret identity?
Clark
Creating your super hero…….
Spider-Man just saved 100 lives!
Oops, Spider-Man was shot dead twice!
Your hero saved a kidnapped kid but was shot once.
—- Superhero information —There are 2 known superheroes.
Name: Spider-Man
Secret Identity: unknown
Status: Dead
People Saved: 100
Name: Superman
Secret Identity: Clark
Status: Alive
People Saved: 11

Submission
Submit your Lab6.java and SuperHero.java to the Submission Server. Go to the Submission Server site
located on the course website, login, then click on Lab Submissions in the left frame. Choose Lab6 from the
dropdown box, click on the browse button and ?nd where you saved your Lab6.java and SuperHero.java
on your computer. Upload the ?les to the site and then click on the Submit button.
Your ?le will be submitted and a screen will show up displaying if your program compiled and what yo