Question

Imagine that you have access to a class named MyCircle that has void setRadius(double r) and double getRadius() methods. Write a static method that accepts a MyCircle array. The method should accomplish two goals: it should return the average of the radius’s for all MyCircles that have a positive radius, and for any MyCircles that have a negative radius it should set the radius to 0.

Answer 1

Code for the method described in the question in java:

public static double averageRadius(MyCircle[] myCircles) {

double sum = 0;

for (MyCircle myCircle: myCircles) {

if(myCircle.getRadius() < 0) myCircle.setRadius(0);

sum += myCircle.getRadius();

}

return sum / myCircles.length;

}

And the complete program:

import java.util.Random;

public class MyCircle {

private double radius;

public double getRadius() {

return radius;

}

public void setRadius(double radius) {

this.radius = radius;

}

public static double averageRadius(MyCircle[] myCircles) {

double sum = 0;

for (MyCircle myCircle: myCircles) {

if(myCircle.getRadius() < 0) myCircle.setRadius(0);

sum += myCircle.getRadius();

}

return sum / myCircles.length;

}

public static void main(String[] args) {

Random random = new Random();

int N = 10;

MyCircle[] myCircles = new MyCircle[N];

for (int i = 0; i < myCircles.length; i++) {

myCircles[i] = new MyCircle();

myCircles[i].setRadius(random.nextInt(100));

System.out.printf("Created MyCircle %d with radius %.2f \\", i, myCircles[i].getRadius());

}

System.out.printf("\\Average radius of %d circles is %.2f \\", N, MyCircle.averageRadius(myCircles));

}

}

The output was:

Created MyCircle 0 with radius 76.00

Created MyCircle 1 with radius 86.00

Created MyCircle 2 with radius 38.00

Created MyCircle 3 with radius 4.00

Created MyCircle 4 with radius 8.00

Created MyCircle 5 with radius 39.00

Created MyCircle 6 with radius 77.00

Created MyCircle 7 with radius 78.00

Created MyCircle 8 with radius 39.00

Created MyCircle 9 with radius 46.00

Average radius of 10 circles is 49.10