Java Inheritance

package Assessment; import java.util.*; public class ParentK { private String initials,studentId; private double grades, fees;

public ParentK(String initials, String studentId, double grades, double fees) { this.fees=fees; this.grades=grades; this.initials=initials; this.studentId=studentId; } public ParentK() {}

public void setGrade(double gr){grades= gr;} public void setFees(double f) {fees=f;} public void setInitials(String in) {initials=in;} public void setStudentId(String st) {studentId=st;}

public double getGrade() {return grades;} public double getFees() {return fees;} public String getInitials() {return initials;} public String getStudentId() {return studentId;}

} public class child extends ParentK{ private int age; public child(String initials, String studentId, double grades, double fees,int age) { super(initials,studentId,grades,fees); this.age=age;

}
public child() {}

public void setAge(int g) {age=g;}
public int getAge() {return age;}

} public class Main1 {

public static void main(String[] args) {
	// encapuslation part
	encap val=new encap("Ittani",25000,25);
  System.out.println("name is " + val.getName());
  System.out.println("Salary is " + val.getSalary());
  System.out.println("Age is " + val.getAge());
  //encapuslation from default constructore

  val.setAge(23);
	val.setName("Skepe");
  val.setSalary(55000);
  System.out.println("\nname is " + val.getName());
  System.out.println("Salary is " + val.getSalary());
  System.out.println("Age is " + val.getAge());

// Area part Area pal= new Area(); pal.setHeight(0.89); pal.setLength(0.23); System.out.println("\n" + "Area="+pal.getArea()+"mm^2"); // Polymorphism polymorphs del = new polymorphs(); System.out.println("\nTwo Subtraction "+ del.add(15, -8)); System.out.println("Three Additions "+ del.add(15, 15, 15)); //Costruction Overloading Box mybox1= new Box(20.2,40.5,62.2); Box mybox2= new Box(); Box circle= new Box(44.2);

 System.out.println("Box 1 volume="+mybox1.vol()+" mm^2");
 System.out.println("Box 2 volume="+mybox2.vol()+" mm^2");
 System.out.println("Box 3 Cycle volume="+circle.vol()+" mm^2");

	Scanner r= new Scanner(System.in);
child op= new child("MA","201604346",80.2,25900,25);
	child op1= new child();
	String in,student;
	double grad, fee;
	int ag;
	
	System.out.println("Enter new student information");
	System.out.println("initials");
	in=r.next();
	System.out.println("student number");
	student=r.next();
	System.out.println("Student Fees");
	fee=r.nextDouble();
	System.out.println("Grades");
	grad=r.nextDouble();
	System.out.println("Student age");
	ag=r.nextInt();
	
	op.setInitials(in);
	op.setStudentId(student);
	op.setAge(ag);
	op.setGrade(grad);
	op.setFees(fee);
	System.out.println("\nInitials="+op.getInitials()+"\nStudentId="+op.getStudentId()+"\nStudent Grades="+op.getGrade()
	+"\nStudent Fees R="+op.getFees()+"\nStudent is "+op.getAge()+" years old");
}

}

Encapsulation

public class encap {

private String name;
private double salary;
private int age;
//constructor
encap(String name, double salary, int age)
{

this.age=age; this.name=name; this.salary=salary; } //default constructor encap() {}

//get Methods
public String getName() {return name;}
public double getSalary() {return salary;}
public int getAge() {return age;}

//set Methods
public void setName(String nam) {name=nam;}
public void setSalary(double sal) {salary=sal;}
public void setAge(int age1) {age=age1;}

} public class Main {

public static void main(String[] args) {
	// encapuslation part
	encap val=new encap("Ittani",25000,25);
  System.out.println("name is " + val.getName());
  System.out.println("Salary is " + val.getSalary());
  System.out.println("Age is " + val.getAge());
  //encapuslation from default constructore

  val.setAge(23);
	val.setName("Skepe");
  val.setSalary(55000);
  System.out.println("\nname is " + val.getName());
  System.out.println("Salary is " + val.getSalary());
  System.out.println("Age is " + val.getAge());

} }

BufferReader, FileReader and FileWriter

import java.io.BufferedReader; import java.io.FileReader; import java.io.FileWriter; public class BufferReader {

public static void main(String[] args) {

	char[] arr= new char[5];
	String data="Ittani is eating";

	try {
		FileReader file= new FileReader("input.txt");
		BufferedReader input= new BufferedReader(file);
		FileWriter fil= new FileWriter("input.txt");
		//Skips 5 characters
		input.skip(5);
		//Read in characters
		input.read(arr);
		//writing the string to the file
		fil.write(data);
		System.out.println("Data in the file");
		System.out.println(arr);
		//closing the reader
		input.close();
	}
	catch(Exception e)
	{
		e.getStackTrace();
	}

Polymorphism

public class Box { double len, wid, hei;

Box(double len, double wid, double hei) { this.hei=hei; this.len=len; this.wid=wid; } Box() {len=wid=hei=0.0;}

Box(double cy) {hei=len=wid=cy;}

double vol() { return len * wid * hei; }

}

public class Main {

public static void main(String[] args) {
Box mybox1= new Box(20.2,40.5,62.2);
  Box mybox2= new Box();
  Box circle= new Box(44.2);
  
 System.out.println("Box 1 volume="+mybox1.vol()+" mm^2");
 System.out.println("Box 2 volume="+mybox2.vol()+" mm^2");
 System.out.println("Box 3 Cycle volume="+circle.vol()+" mm^2");
}