Write a program to show the difference between public and private access specifiers. The program should also show that primitive data types are passed by value and objects are passed by reference and to learn use of final keyword

Write a program to show the difference between public and private access specifiers. The program should also show that primitive data types are passed by value and objects are passed by reference and to learn use of final keyword.

Program:

class Distance {

  public int feet, inches;

  private int metrs, centimetrs;

  public final int kilo = 1000;//final keyword

  Distance(int f, int i) {

    metrs = 100;

    centimetrs = 50;

    this.feet = f;

    this.inches = i;

  }

  void display() {

    System.out.println("feet=  " + feet);

    System.out.println("inches=   " + inches);

    System.out.println("metres=  " + metrs);

    System.out.println("centimetrs=   " + centimetrs);

  }

  void addDistance(Distance d3) {

    // kilo=2000; //because of final value can't be assigned

    d3.feet = d3.feet + kilo;

    d3.inches = d3.inches + kilo;

  }

}

public class Main {

  public static void main(String args[]) {

    Distance d1 = new Distance(10, 20);

    Distance d3 = new Distance(20, 30);

    d1.display();

    // System.out.println("metres= "+d1.metrs);

    // metrs can't be accessed because of private access specifier

    // System.out.println("centimetres= "+d1.centimetrs);

    // centimeters can't be accessed because of private access specifier

    d1.addDistance(d3);

    d3.display();

  }

}

OutPut:

feet=  10

inches=   20

metres=  100

centimetrs=   50

feet=  1020

inches=   1030

metres=  100

centimetrs=   50