Chapter 13.2, Problem 13.2.1CP

Program Plan Intro

a)

“abstract” class:

An abstract class is a class which may or may not include abstract methods and cannot be instantiated but rather it can be sub classed.

Legal “abstract” class:

• The conditions for a class to be considered as legal abstract class are mentioned below:
  • If a class includes abstract methods, then the class must be declared as abstract.
  • The abstract method that is declared within the abstract class must be declared without braces and followed by a semicolon.

Example of a Legal “abstract” class:

The example of a legal abstract class is mentioned below:

public abstract class GraphicRectangle {

//declare fields

//declare methods

abstract void drawRectangle();

}

Given code:

//class definition

class A {

  //declaration of an abstract method

  abstract void unfinished() {

  }

//end of class

}

Program Plan Intro

b)

“abstract” class:

An abstract class is a class which may or may not include abstract methods and cannot be instantiated but rather can be sub classed.

Legal “abstract” class:

The conditions for a class to be considered as legal abstract class are mentioned below:

• If a class includes abstract methods, then the class must be declared as abstract.
• The abstract method that is declared within the abstract class must be declared without braces and followed by a semicolon.

Example of a Legal “abstract” class:

The example of a legal abstract class is mentioned below:

public abstract class GraphicRectangle {

//declare fields

//declare methods

abstract void drawRectangle();

}

Given code:

//class definition

public class abstract A {

  //declaration of an abstract method

  abstract void unfinished();

//end of class

}

Program Plan Intro

c)

“abstract” class:

An abstract class is a class which may or may not include abstract methods and cannot be instantiated but rather can be sub classed.

Legal “abstract” class:

The conditions for a class to be considered as legal abstract class are mentioned below:

• If a class includes abstract methods, then the class must be declared as abstract.
• The abstract method that is declared within the abstract class must be declared without braces and followed by a semicolon.

Example of a Legal “abstract” class:

The example of a legal abstract class is mentioned below:

public abstract class GraphicRectangle {

//declare fields

//declare methods

abstract void drawRectangle();

}

 Given code:

//class definition

class A {

  //declaration of an abstract method

  abstract void unfinished();

   //end of class

   }

Program Plan Intro

d)

“abstract” class:

An abstract class is a class which may or may not include abstract methods and cannot be instantiated but rather can be sub classed.

Legal “abstract” class:

The conditions for a class to be considered as legal abstract class are mentioned below:

• If a class includes abstract methods, then the class must be declared as abstract.
• The abstract method that is declared within the abstract class must be declared without braces and followed by a semicolon.

Example of a Legal “abstract” class:

The example of a legal abstract class is mentioned below:

public abstract class GraphicRectangle {

//declare fields

//declare methods

abstract void drawRectangle();

}

 Given code:

//class definition

abstract class A {

        //declaration of a protected method

         protected void unfinished();

   //end of class

}

Program Plan Intro

e)

“abstract” class:

An abstract class is a class which may or may not include abstract methods and cannot be instantiated but rather can be sub classed.

Legal “abstract” class:

The conditions for a class to be considered as legal abstract class are mentioned below:

• If a class includes abstract methods, then the class must be declared as abstract.
• The abstract method that is declared within the abstract class must be declared without braces and followed by a semicolon.

Example of a Legal “abstract” class:

The example of a legal abstract class is mentioned below:

public abstract class GraphicRectangle {

//declare fields

//declare methods

abstract void drawRectangle();

}

 Given code:

//class definition

abstract class A {

        //declaration of an abstract method

          abstract void unfinished();

//end of class

}

Program Plan Intro

f)

“abstract” class:

An abstract class is a class which may or may not include abstract methods and cannot be instantiated but rather can be sub classed.

Legal “abstract” class:

The conditions for a class to be considered as legal abstract class are mentioned below:

• If a class includes abstract methods, then the class must be declared as abstract.
• The abstract method that is declared within the abstract class must be declared without braces and followed by a semicolon.

Example of a Legal “abstract” class:

The example of a legal abstract class is mentioned below:

public abstract class GraphicRectangle {

//declare fields

//declare methods

abstract void drawRectangle();

}

Given code:

//class definition

abstract class A {

        //declaration of an abstract method

          abstract int unfinished();

//end of class

}