Using Objects Home | Objects & Void Methods | Methods | String Objects | Wrapper Classes & Math Module | Review |
Unit 2 — Recap & Homework
A recap of everything we covered today.
Homework
Now, it’s time to practice! The following problem will incorporate the following concepts:
- Classes
- Constructors
- Methods
- Void methods
- Non-void methods
- Math class
Integer
andDouble
wrapper classes- String methods
public class Circle {
// 1. Class variable: radius (double)
// 2. Make a constructor that takes in the radius as a parameter, and sets the radius property
// 3. cirumference() method: Calculate and return the circumference
// 4. area() method: Calculate and return the area, use Math.pow()
public double radius;
Circle(double radius){
this.radius=radius;
}
public double circumference(){
return this.radius*2*3.14;
}
public double area(){
return 3.14*Math.pow(this.radius,2);
}
}
public class Student {
// 1. Class variables: name (String) and grade (Integer)
// 2. Constructor to initialize name and grade
// 3. nameLength() method: Return the length of the student's name
// 4. getGradeAsDouble() method: Return the grade as the Double wrapper type
// 5. getScaledGrade() method: Return grade divided by 2
public String name;
public int grade;
Student(String name, int grade){
this.name=name;
this.grade=grade;
}
public int nameLength(){return this.name.length();}
public double getGradeAsDouble(){return (double)this.grade;}
public int getScaledGrade(){return grade/2;}
}
public class Main {
public static void main(String[] args) {
// Testing the Circle class
Circle circle1 = new Circle(5.0);
Circle circle2 = new Circle(7.0);
System.out.println("Circle 1:");
System.out.println("Radius: " + circle1.radius);
System.out.println("Circumference: " + circle1.circumference());
System.out.println("Area: " + circle1.area());
System.out.println("\nCircle 2:");
System.out.println("Radius: " + circle2.radius);
System.out.println("Circumference: " + circle2.circumference());
System.out.println("Area: " + circle2.area());
// Testing the Student class
Student student1 = new Student("Aadit", 75);
Student student2 = new Student("Emily", 45);
System.out.println("\nStudent 1:");
System.out.println("Name: " + student1.name);
System.out.println("Name Length: " + student1.nameLength());
System.out.println("Grade: " + student1.getGradeAsDouble());
System.out.println("Scaled Grade: " + student1.getScaledGrade());
System.out.println("\nStudent 2:");
System.out.println("Name: " + student2.name);
System.out.println("Name Length: " + student2.nameLength());
System.out.println("Grade: " + student2.getGradeAsDouble());
System.out.println("Scaled Grade: " + student2.getScaledGrade());
}
}
Main.main(null);
Circle 1:
Radius: 5.0
Circumference: 31.400000000000002
Area: 78.5
Circle 2:
Radius: 7.0
Circumference: 43.96
Area: 153.86
Student 1:
Name: Aadit
Name Length: 5
Grade: 75.0
Scaled Grade: 37
Student 2:
Name: Emily
Name Length: 5
Grade: 45.0
Scaled Grade: 22