Fall 2018, Siena College

Circles BlueJ Project

Circles Source Code

The Java source code for Circles is below. Click on a file name to download it.

### Circle.java

```
/**
* Representation of a circle in the plane
*
* @author Jim Teresco and the CSIS 210 class
*/
public class Circle
{

// instance variables
private double centerX;
private double centerY;

// default constructor, circle at the origin of
// radius 1 for lack of a better obvious option
public Circle() {

centerX = 0.0;
centerY = 0.0;
}

// general-purpose constructor
public Circle(double x, double y, double r) {

centerX = x;
centerY = y;
}

// toString for printing
public String toString() {
return "center (" + centerX + "," + centerY + "), radius " +
}

// compute our circumference
public double circumference() {

return 2 * radius * Math.PI;
}

// compute the area
public double area() {

}

// trivial getters and setters
public void setCenterX(double cx) {

centerX = cx;
}

public void setCenterY(double cy) {

centerY = cy;
}

}

// alternate mutators
public void setDiameter(double d) {

}

// set both coordinates of the center
public void setCenter(double x, double y) {

centerX = x;
centerY = y;
}

// translate the circle by dx, dy
public void moveBy(double dx, double dy) {

centerX += dx;
centerY += dy;
}

// scale the circle in place
public void scale(double s) {

}

// a method to call to print out lots of information about our circle
public void printInfo() {

System.out.println(this);
System.out.println("Circumference: " + circumference() + ", area: " + area());
}

// a main method to try out a lot of these
public static void main(String args[]) {

Circle def = new Circle();
System.out.println("Default circle: " + def);
System.out.println("its circumference: " + def.circumference());

Circle c1 = new Circle(2, 4, 5);
System.out.println("c1: " + c1);
System.out.println("its circumference: " + c1.circumference());

Circle c2 = new Circle(3.5, 9.0, 3.0);
System.out.println("c2 on construction:");
c2.printInfo();
c2.setDiameter(0.25);
System.out.println("After setDiameter(0.25)");
c2.printInfo();
c2.setCenter(0, 100);
System.out.println("After setCenter(0, 100)");
c2.printInfo();
c2.scale(1000);
System.out.println("After scale(1000)");
c2.printInfo();
c2.moveBy(-34.2, 982.1);
System.out.println("After moveBy(-34.2, 982.1)");
c2.printInfo();

}

}
```