Java Novice Note 17 parameters

Package Com.yfs.javase;public class Paramdemo {public static void main (string[] args) {int a = 3, B = 5;change (a); System.out.println ("a =" + a  + "  B =" + B); Point P = new Point ();p. x = 10;p.y = 20;change (p); System.out.println ("p.x =" + p.x  + "  p.y =" + p.y);} public static void Change (point P) {//reference pointing to  is an object int c = p.x;p.x = P.y;p.y = C;} public static  void change (int a, int b) {//local variable  passed in is numeric System.out.println ("================"); System.out.println ("|  | | | | | | A = "+ a  +"  B = "+ B +" | | | | | | "); int c = A;a = B;b = C; System.out.println ("|  | | | | | | A = "+ a  +"  B = "+ B +" | | | | | | "); System.out.println ("================");}} Class Point {int x;int y;}

1.Person

Package Com.yfs.javase;public class Person {public person () {System.out.println ("javase. Person  * * * ");}}

2. Other person

Package Com.yfs.javase.other;public class Person {public person () {System.out.println (' other '). Person object ... ");}

3.Person Test

Package Com.yfs.javase.other;import Com.yfs.javase.person;public class Persontest {/** * @param args */public static void Main (string[] args) {person P1 = new person (); Com.yfs.javase.other.Person P2 = new Com.yfs.javase.other.Person ();}}

4.default

Package com.yfs.javase.other; Class Defaultdemo {}  class other {    }    /*public*/class Demo {    }

5. Public class

Package com.yfs.javase.other;//A Java file can have only one public decorated class//class with the same name as the file public/*final*/class Publicclass {private String name ;p ublic int age;protected char sex;int score; static final int id;//= 520;//only one copy of all objects shared static {id = 200;} Public Publicclass () {//id = 100;} The permissions of the method public final void Publicmethod () {//id = 350;} private void Privatemethod () {Protectedmethod ();} protected void Protectedmethod () {}    /*default*/void Defaultmethod () {Protectedmethod ();}} /*default  public*/class Defaultclass {}

6. Testing

Package com.yfs.javase.other;//under Common class AccessTest1 {public static void main (string[] args) {Publicclass pc = new Publicclass ();p c.publicmethod ();//pc.privatemethod (); Private methods cannot access Pc.protectedmethod ();p c.defaultmethod ();    Pc.age =;    Pc.score = 90;}}

7. Out-of-package testing

Package Com.yfs.javase;import com.yfs.javase.other.publicclass;//under different packages public class AccessTest2 {public static void main (string[] args) {Publicclass pc = new Publicclass ();p c.publicmethod ();//pc.privatemethod (); Private method cannot access//pc.protectedmethod (); The protected method cannot access the//pc.defaultmethod ();d Efautl method cannot access}}class child  extends Publicclass {public void Test () {// Privatemethod ();p rotectedmethod ();//subclass can access//defaultmethod ();//different packages cannot access}//@Override//public final void Publicmethod () {////TODO auto-generated method stub////}}

Java Novice Note 17 parameters