Unit 2 — Recap & Homework

• Homework

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 and Double wrapper classes
• String methods

public class Circle {

    public double radius;

    public Circle(double radius) {
        this.radius = radius;
    }

    public double circumference() {
        return 2 * Math.PI * radius;
    }

    public double area() {
        return Math.PI * Math.pow(radius, 2);
    }
}

public class Student {
    public String name;
    public Integer grade;

// Constructor 
    public Student(String name, int grade) {
        this.name = name;
        this.grade = new Integer(grade);
    }

    public int nameLength() {
        return name.length();
    }

    public Double getGradeAsDouble() {
        return new Double((double) grade);
    }

    public Double getScaledGrade() {
        return Double.valueOf(getGradeAsDouble() / 2);
    }
}

public class Main {
    public static void main(String[] args) {

        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("\n circle 2");
        System.out.println("radius: " + circle2.radius);
        System.out.println("circumference: " + circle2.circumference());
        System.out.println("area: " + circle2.area());


        Student student1 = new Student("Alisha", 75);
        Student student2 = new Student("Anika", 45);

        System.out.println("\n student 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("\n student 2");
        System.out.println("nname: " + 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: 31.41592653589793
area: 78.53981633974483

 circle 2
radius: 7.0
circumference: 43.982297150257104
area: 153.93804002589985

 student 1
name: Alisha
name length: 6
grade: 75.0
scaled grade: 37.5

 student 2
nname: Anika
name Length: 5
GRade: 45.0
scaled Grade: 22.5