Lesson 15

Calculator.java

package computer;

import java.util.Locale;
import java.util.Scanner;

public class Calculator {
    private double resultValue;
    private double divResultValue;
    private double numberBeforeSquareRootExtraction;
    private double squareRootCalcResult;
    private double angleBeforeSineCalc;
    private double sineCalcResult;
    private double operand1;
    private String operation;
    private double operand2;
    private boolean computerStatus;


    public double getSum(double operand1, double operand2) {
        return resultValue = operand1 + operand2;
    }

    public void printResult(double resultValue) {
        System.out.println("Result value: " + resultValue);
    }

    public double getDiv(double firstNumber, double secondNumber) {
        return divResultValue = firstNumber / secondNumber;
    }

    /* BEGIN methods of Math class */

    public double getSqrt(double numberBeforeSquareRootExtraction) {
        this.numberBeforeSquareRootExtraction = numberBeforeSquareRootExtraction;
        return squareRootCalcResult = Math.sqrt(numberBeforeSquareRootExtraction);
    }

    public double getSine(double angleBeforeSineCalc) {
        this.angleBeforeSineCalc = angleBeforeSineCalc;
        return sineCalcResult = Math.sin(angleBeforeSineCalc);
    }

    public void runCalculator(boolean computerStatus) throws ComputerAccessException {
        this.computerStatus = computerStatus;
        if (computerStatus) {
            System.out.println("Computer works");
        } else {
            throw new ComputerAccessException("You can't use this program because computer is off\n");
        }
    }
    /* Array */

    public void findMaxInAnArray(int[] array) {
        int max = array[0];
        for (int i = 0; i < array.length; i++) {
            if (max < array[i])
                max = array[i];
        }
        System.out.println("Maximum in an array: " + max);
    }

    public void storeResultInAnArray(Object[][] twoDimArray) {
        for (int row = 0; row < twoDimArray.length; row++) {
            for (int column = 0; column < twoDimArray.length; column++) {
                System.out.print(twoDimArray[row][column] + "\t");
            }
            System.out.println();
        }
    }

    public static void main(String[] args) {
        Calculator myCalc = new Calculator();
        try {
            myCalc.runCalculator(false);
        } catch (ComputerAccessException e) {
            System.err.print(e);
        }
        double resultValue = myCalc.getSum(myCalc.operand1, myCalc.operand2);
        myCalc.printResult(resultValue);
        myCalc.getDiv(10, 2);
        myCalc.getSqrt(100.0);
        myCalc.getSine(30.0);
        int[] array = {12, 1, 5, -11, 7, 13, -1, -5};
        myCalc.findMaxInAnArray(array);
        System.out.println("The square root of \"" + myCalc.numberBeforeSquareRootExtraction + "\" is: " + myCalc.squareRootCalcResult);
        System.out.println("The sine of \"" + myCalc.angleBeforeSineCalc + "\" is: " + myCalc.sineCalcResult);
        System.out.println("\nType two numbers with symbol betwin them. For example 10 + 5. You can use: + - * /");
        Scanner dataInput = new Scanner(System.in);
        try {
            dataInput.useLocale(Locale.ENGLISH);
            myCalc.operand1 = dataInput.nextDouble();
            myCalc.operation = dataInput.next();
            myCalc.operand2 = dataInput.nextDouble();
        } catch (Exception e) {
            dataInput.useLocale(Locale.FRANCE);
            myCalc.operand1 = dataInput.nextDouble();
            myCalc.operation = dataInput.next();
            myCalc.operand2 = dataInput.nextDouble();
        }
        switch (myCalc.operation) {
            case "+": {
                myCalc.getSum(myCalc.operand1, myCalc.operand2);
                myCalc.printResult(myCalc.resultValue);
            }
            break;
            case "-":
                System.out.println(myCalc.operand1 + " - " + myCalc.operand2 + " = " + (myCalc.operand1 - myCalc.operand2));
                break;
            case "*":
                System.out.println(myCalc.operand1 + " * " + myCalc.operand2 + " = " + (myCalc.operand1 * myCalc.operand2));
                break;
            case "/":
                System.out.println(myCalc.operand1 + " / " + myCalc.operand2 + " = " + (myCalc.operand1 / myCalc.operand2));
                break;
            default:
                System.out.println("You have a typo, try again");
                break;
        }
        Object[][] twoDimArray = new Object[2][2];
        twoDimArray[0] = new String[]{"sum", "division"};
        twoDimArray[1] = new Double[]{myCalc.resultValue, myCalc.divResultValue};
        myCalc.storeResultInAnArray(twoDimArray);
    }

}

Computer.java

package computer;

import java.util.Scanner;

public class Computer implements java.io.Serializable { // Creating class Computer
    private int powerSupply; // fields
    private float processor;
    private int videoCard;
    private String motherBoard;

    public Computer() { // default constructor
    }

    /* getter and setter methods
    BEGIN powerSupply */
    public int getPowerSupply() {
        return powerSupply;
    }

    public void setPowerSupply(int powerSupply) {
        this.powerSupply = powerSupply;
    }

    // BEGIN processor
    public float getProcessor() {
        return processor;
    }

    public void setProcessor(float processor) {
        this.processor = processor;
    }

    // BEGIN videoCard
    public int getVideoCard() {
        return videoCard;
    }

    public void setVideoCard(int videoCard) {
        this.videoCard = videoCard;
    }

    // BEGIN motherBoard
    public String getMotherBoard() {
        return motherBoard;
    }

    public void setMotherBoard(String motherBoard) {
        this.motherBoard = motherBoard;
    }

    public void turnOnComputer() {
        System.out.println("Type 1 and press Enter to turn me on");
        System.out.println("Type 2 if don't wanna please me");
        Scanner sc = new Scanner(System.in);
        switch (sc.nextInt()) {
            case 1:
                System.out.println("It's alive!");
                chooseWhatToDoNext();
                break;
            case 2:
                System.out.println("Give me the power and nobody gets hurt! Please!");
                System.out.println("Computer power not turned on. Do you know what \"eien\" means in Japanese?\n"); // it means "eternity"
                turnOnComputer();
                break;
            default:
                System.out.println("You can choose only between 1 and 2");
                turnOnComputer();
                break;
        }
    }

    public void chooseWhatToDoNext() {
        System.out.println("What do you want to do next?");
        System.out.println("Type 1 to shut down. Type 2 to install operating system");
        Scanner sc = new Scanner(System.in);
        switch (sc.nextInt()) {
            case 1:
                turnOffComputer();
                break;
            case 2:
                chooseOSToInstall();
                break;
            default:
                System.out.println("You can choose only between 1 and 2");
                chooseWhatToDoNext();
                break;
        }
    }

    public void turnOffComputer() {
        System.out.println("Shutting down. Done.");
    }

    public void chooseOSToInstall() {
        System.out.println("What OS do you want to install?");
        System.out.println("\t 1 Apple OS X \n\t 2 FreeBSD \n\t 3 GNU/Linux \n\t 4 Windows \n\t 5 To go back");
        Scanner sc = new Scanner(System.in);
        switch (sc.nextInt()) {
            case 1:
            case 2:
            case 3:
            case 4:
                installOS();
                break;
            case 5:
                chooseWhatToDoNext();
                break;
            case 6:

            default:
                chooseOSToInstall();
                break;
        }
    }

    public void installOS() {
        System.out.println("Installed");
        System.out.println("Do you want to boot OS and install some software?");
        System.out.println("Type 1 to boot OS. Type 2 to shut down.");
        Scanner sc = new Scanner(System.in);
        switch (sc.nextInt()) {
            case 1:
                bootOS();
                break;
            case 2:
                turnOffComputer();
                break;
        }
    }

    public void bootOS() {
        System.out.println("Booted");
        System.out.println("You can install Calculator and FileManager.");
        System.out.println("\t 1 Install both; \n\t 2 Install Calculator \n\t 3 Install FileManager");
        Scanner sc = new Scanner(System.in);
        switch (sc.nextInt()) {
            case 1:
                installCalculator();
                installFileManager();
                break;
            case 2:

                installCalculator();
                break;
            case 3:
                installFileManager();
                break;
            case 4:
                turnOffComputer();
                break;
            default:
                System.out.println("You can choose only between 1 and 2");
                bootOS();
                break;
        }
    }

    public void installCalculator() {
        System.out.println("Calculator installed");
    }

    public void installFileManager() {
        System.out.println("FileManager installed");
    }
}

ComputerAccessException.java

package computer;

public class ComputerAccessException extends Exception {
    // Default constructor
    public ComputerAccessException() {
    }

    // Constructor that accepts a message
    public ComputerAccessException(String message) {
        super(message);
    }

}

FileManager.java

package computer;

import java.io.*;

public class FileManager {

    public static void copyFile(String firstFile, String secondFile) throws Exception {
        try (
                BufferedReader br = new BufferedReader(new FileReader(firstFile));
                PrintWriter pw = new PrintWriter(new FileWriter(secondFile))
        ) {
            int line;
            while ((line = br.read()) != -1) {
                pw.write(line);
            }
            System.out.println("All done");
        } catch (FileNotFoundException e) {
            System.out.println(firstFile + " not found");
        }

    }

    public static void deleteFile(String fileToBeDeleted) {

        try {
            File file = new File(fileToBeDeleted);
            if (file.delete()) {
                System.out.println(file.getName() + " is deleted");
            } else {
                System.out.println("deletion failed");
            }
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

    public static void main(String[] args) throws Exception {
        String firstFile = "first.txt";
        String secondFile = "second3.txt";
        String fileToBeDeleted = "second3.txt";
        copyFile(firstFile, secondFile);
        deleteFile(fileToBeDeleted);
    }
}

Main.java

package computer;

public class Main {

    public static void main(String args[]) {
        Computer myComp = new Computer(); //  object myComp
        myComp.setPowerSupply(450);
        myComp.setProcessor(2.4f);
        myComp.setVideoCard(11);
        myComp.setMotherBoard("Asus P5K");
        myComp.turnOnComputer();
        System.out.println(myComp.getPowerSupply() + "\n" + myComp.getProcessor()
                + "\n" + myComp.getVideoCard() + "\n" + myComp.getMotherBoard());
    }
}