classes, Person tester, Exercise 03 slide 48

package class170706;

import java.util.Arrays;
import java.util.Random;

public class PersonTester {

    public static void main(String[] args) {
        // create an object for random numbers
        Random rnd = new Random();

        // create a persons array
        Person[] personsArr = new Person[10];

        // create each person in the array with random height and weight

        System.out.println("source data in the array");
        for (int i = 0; i < personsArr.length; i += 1) {
            // create a person with default values
            personsArr[i] = new Person();

            // update each person properties
            personsArr[i].setName("Person-" + i);
            personsArr[i].setHeight(1 + rnd.nextInt(250));
            personsArr[i].setWeight(1 + 150 * rnd.nextDouble());

            System.out.printf("[%d] : %s\n", i, personsArr[i]);
        }

        // sorting array by weight, using insert sort algorithm
        sortByWeight(personsArr);
        System.out.println("\narray sorted by weight:");
        for (int i = 0; i < personsArr.length; i += 1) {
            System.out.printf("[%d] : %s\n", i, personsArr[i]);
        }

        // sorting array by height, using bubble sort algorith
        sortByHeight(personsArr);
        System.out.println("\narray sorted by height:");
        for (int i = 0; i < personsArr.length; i += 1) {
            System.out.printf("[%d] : %s\n", i, personsArr[i]);
        }

        // sorting arra by name, using Arrays.sort method
        sortByName(personsArr);
        System.out.println("\narray sorted by name:");
        for (int i = 0; i < personsArr.length; i += 1) {
            System.out.printf("[%d] : %s\n", i, personsArr[i]);
        }

    }

    // sorting persons array by weight, using insert sort
    public static void sortByWeight(Person[] personsArray) {
        int startIndex = 0; // first element to checked. elements before that
                            // are already sorted

        while (startIndex < personsArray.length - 1) {
            // initialize minimum weight and and its index
            int minIndex = startIndex;
            double minWeight = personsArray[startIndex].getWeight();

            // start scanning in the array
            for (int i = startIndex + 1; i < personsArray.length; i += 1) {
                // find the minimum weight and its index
                if (personsArray[i].getWeight() < minWeight) {
                    minIndex = i;
                    minWeight = personsArray[i].getWeight();
                }
            }

            // put the person with minimum weight at startIndex
            if (minIndex != startIndex) {
                Person tempPerson = personsArray[startIndex];
                personsArray[startIndex] = personsArray[minIndex];
                personsArray[minIndex] = tempPerson;
            }
            // now start searching from the next cell
            startIndex += 1;
        }
    }

    // sorting persons array by height, using bubble sort
    public static void sortByHeight(Person[] personsArray) {
        boolean isOrderd; // true when the array is sorted
        int lastIndex = personsArray.length - 1; // last active index in the
                                                    // array

        // start switching unordered elements
        do {
            isOrderd = true; // initialization

            // scan all active cells in the array (0 to lastIndex)
            for (int i = 0; i < lastIndex; i += 1) {
                // if persons are not orderd
                if (personsArray[i].getHeight() > personsArray[i + 1]
                        .getHeight()) {
                    // switch them
                    Person tempPerson = personsArray[i];
                    personsArray[i] = personsArray[i + 1];
                    personsArray[i + 1] = tempPerson;

                    // mark array as unordered to make another round
                    isOrderd = false;
                }
            }
            // last index now containing the right element
            // stop before it next time (mark it as unActive)
            lastIndex -= 1;
        } while (!isOrderd); // loop until the array is ordered
    }

    // sorting persons array by name, using Array.sort method
    public static void sortByName(Person[] personsArray) {
        Arrays.sort(personsArray, (person1, person2) -> person1.getName()
                .compareTo(person2.getName())); // compare two persons by
                                                // comparing their names

    }

}