JavaExercises/Java 3/HW1Lesson.java at master · biblelamp/JavaExercises · GitHub

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/**

* Java. Level 3. Lesson 1. Homework

* 1. Write a method which changes the places of the two elements of the array.

* (array can be of any reference type)

* 2. Write method which converts an array in ArrayList

* 3. "Big task" about fruits (apples, oranges) and baskets (box)

* @author Sergey Iryupin

* @version Feb 03, 2018

import java.util.ArrayList;

import java.util.Arrays;

public class HW1Lesson {

public static void main(String[] args) {

HW1Lesson hw = new HW1Lesson();

// tasks 1, 2

String[] strings = {"First", "Second", "Third", "Fourth", "Five"};

System.out.println(hw.convertArrayToList(strings)); // task 2

hw.swapElements(0, 2, strings);

System.out.println(Arrays.toString(strings));

Integer[] numbers = {1, 2, 3, 4, 5, 6};

System.out.println(hw.convertArrayToList(numbers)); // task 2

hw.swapElements(0, 2, numbers);

System.out.println(Arrays.toString(numbers));

// task 3

Box<Apple> appleBox = new Box<>();

Box<Orange> orangeBox = new Box<>();

for (int i = 0; i < 5; i++) {

appleBox.add(new Apple());

orangeBox.add(new Orange());

}

System.out.println(appleBox.getFruits());

System.out.println(orangeBox.getFruits());

Box<Apple> appleBox1 = new Box<>();

appleBox1.add(new Apple());

appleBox.moveAllToNextBox(appleBox1);

System.out.println(appleBox.getFruits());

System.out.println(appleBox1.getFruits());

}

private <T> void swapElements(int idx1, int idx2, T[] array) {

T tmp = array[idx1];

array[idx1] = array[idx2];

array[idx2] = tmp;

}

private <T> ArrayList<T> convertArrayToList(T[] array) {

return new ArrayList<>(Arrays.asList(array));

}

class Box<T extends Fruit> {

private ArrayList<T> fruits;

public Box() {

fruits = new ArrayList<>();

}

public void add(T fruit) {

fruits.add(fruit);

}

public void addFruits(ArrayList<T> fruits) {

this.fruits.addAll(fruits);

}

public ArrayList<T> getFruits() {

return fruits;

}

public float getWeight() {

float totalWeight = 0.0f;

for (T fruit : fruits)

totalWeight += fruit.getWeight();

return (float)Math.ceil(totalWeight * 100)/100;

}

public boolean compare(Box<?> box) {

return Float.compare(getWeight(), box.getWeight()) == 0;

}

public void moveAllToNextBox(Box<T> box) {

box.addFruits(getFruits());

fruits.clear();

}

class Apple extends Fruit {

public Apple() {

super(0.7f + (float)Math.random()/3);

}

class Orange extends Fruit {

public Orange() {

super(1.2f + (float)Math.random()/3);

}

abstract class Fruit {

protected float weight;

public Fruit(float weight) {

this.weight = weight;

}

public float getWeight() {

return weight;

}

@Override

public String toString() {

return this.getClass().getName() + "=" + Math.ceil(weight * 100)/100;

}

JavaExercises/Java 3/HW1Lesson.java at master · biblelamp/JavaExercises · GitHub

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