Java Basic 1

1. Variable Length Arguments:
public static void main(String[] args) {
// TODO Auto-generated method stub
System.out.println(avg(5,2,3,5,6,7));
System.out.println(avg(10,11,21,33));

}

public static int avg(int...numbers){
int t = 0;
for(int x: numbers)
t+=x;
return t/numbers.length;
}

2. Enumeration and EnumSet range:
public enum someClass {
bucky("nice", "22"),
kelsey("cutie", "10"),
julia("bigmistake", "12"),
bataa("cool","25"),
azaa("good", "15");

final String desc;
final String year;

someClass(String de, String b){
desc = de;
year = b;
}
public String getDesc(){
return desc;
}
public String getYear(){
return year;
}

}

mainclass:
public static void main(String[] args) {
// TODO Auto-generated method stub

for(someClass c: EnumSet.range(someClass.kelsey, someClass.bataa))
//for(someClass c: someClass.values())

System.out.printf("%s\t%s\t%s\n", c, c.desc, c.year);

}
3. Static Example:
public class someClass {
String fname;
String lname;
static int members=0;

someClass(String f, String l){
fname = f;
lname = l;
members++;
System.out.printf("\nNew Member firstname: %s, lastname: %s, Id: %d", fname, lname, members);
}
public String getFname(){
return fname;
}
public String getLname(){
return lname;
}
public int getMembers(){
return members;
}
}

mainClass:
public static void main(String[] args) {
// TODO Auto-generated method stub
someClass sc1 = new someClass("Carmelo", "Anthony");
someClass sc2 = new someClass("Lebron", "James");
someClass sc3 = new someClass("Chris", "Paul");

System.out.println("\n" + sc1.getMembers());

}

Array Holding Many Objects:
 public class someClassList {

     

      someClass[] sc = new someClass[5];

      int i = 0;

     

      public void add(someClass s){

            if(i<sc.length)

            {

                  sc[i] = s;

                  System.out.println("some class added by index: " + i);

                  i++;

                  }

            }

}

B.  public class OtherClass extends someClass{

}

C.  public class someClass{

}    

Main class:

public class func1{

     

      public static void main(String[] args) {

            // TODO Auto-generated method stub

            someClassList scl = new someClassList();

            OtherClass os = new OtherClass();

            someClass sc = new someClass();

            scl.add(os);

            scl.add(sc);

           

      }

}

Simple Polymorphic:

public class someClass{

     

      public void noise(){

            System.out.println("Base class noise");

      }

}

public class OtherClass extends someClass{

      public void noise(){

            System.out.println("OtherCLass noise");

      }

}

Main Class:

      public static void main(String[] args) {

            // TODO Auto-generated method stub

            OtherClass os = new OtherClass();

            os.noise();

            someClass sc = new someClass();

            sc.noise();

      }

File

Creating Files:

      public static void main(String[] args) {

            // TODO Auto-generated method stub

            final Formatter x;

            try{

                  x = new Formatter("javatutorial.txt");

                  System.out.println("You created a file!");

                 

            }catch(Exception ex){

                  System.out.println(ex.getMessage());

            }

      }

Writing to Files:

public class someClass{

     

      private Formatter x;

      public void openFile(){

            try{

                  x = new Formatter("javaa.txt");    

            } catch (Exception ex){

                  System.out.println(ex.getMessage());

            }

      }

      public void addRecords(){

            x.format("%s%s%s", "15", "Carmelo", "Anthony");

      }

      public void closeFile(){

            x.close();

      }

}

Main class:

      public static void main(String[] args) {

            // TODO Auto-generated method stub

            someClass sc = new someClass();

            sc.openFile();

            sc.addRecords();

            sc.closeFile();

      }

Reading to Files:

 public class someClass{

      private Scanner x;

     

      public void openFile(){

            try{

                  x = new Scanner(new File("javaa.txt"));

            } catch (Exception ex){

                  System.out.println(ex.getMessage());

            }

      }

     

      public void readFile(){

            String a, b, c;

            while(x.hasNext()){

                  a = x.next();

                  b = x.next();

                  c = x.next();

                  System.out.printf("%s %s %s\n", a, b, c);

            }

      }

     

      public void closeFile(){

            x.close();

      }

}

Main class:

      public static void main(String[] args) {

            // TODO Auto-generated method stub

            someClass sc = new someClass();

            sc.openFile();

            sc.readFile();

            sc.closeFile();

      } 

Видео линк:https://www.youtube.com/playlist?list=PLFE2CE09D83EE3E28