method abstraction

1// abstraction in java with example
2// abstract class
3abstract class Addition
4{
5   // abstract methods
6   public abstract int addTwoNumbers(int number1, int number2);
7   public abstract int addFourNumbers(int number1, int number2, int number3, int number4);
8   // non-abstract method
9   public void printValues()
10   {
11      System.out.println("abstract class printValues() method");
12   }
13}
14class AbstractMethodExample extends Addition
15{
16   public int addTwoNumbers(int number1, int number2)
17   {
18      return number1 + number2;
19   }
20   public int addFourNumbers(int number1, int number2, int number3, int number4)
21   {
22      return number1 + number2 + number3 + number4;
23   }
24   public static void main(String[] args)
25   {
26      Addition add = new AbstractMethodExample();
27      System.out.println(add.addTwoNumbers(6, 6));
28      System.out.println(add.addFourNumbers(8, 8, 3, 2));
29      add.printValues();
30   }
31}

1// example on abstract class in java
2import java.util.*;
3// abstract class
4abstract class Shape
5{
6   // abstract method
7   abstract void sides();
8}
9class Triangle extends Shape
10{
11   void sides()
12   {
13      System.out.println("Triangle shape has three sides.");
14   }
15}
16class Pentagon extends Shape
17{
18   void sides()
19   {
20      System.out.println("Pentagon shape has five sides.");
21   }
22   public static void main(String[] args)
23   {
24      Triangle obj1 = new Triangle();
25      obj1.sides();
26      Pentagon obj2 = new Pentagon();
27      obj2.sides();
28   }
29}

1 // Method abstraction is the practice of reducing inter-dependency between methods.  
2 // The following is an unreasonably simple example, but the point stands: 
3 // don't make the person on the other side of your function do more work 
4 // than they need to.  Include all necessary data transformations in your 
5 // methods as is.  For instance, take method GetAreaOfCircle: 
6
7 // Good practice: 
8float GetAreaOfCircle(float radius) {
9	return 3.14f * radius * radius;
10}
11int main() {
12	printf("%d", GetAreaOfCircle(3.0f));
13    getch();
14    return 0;
15}
16
17 // Bad practice: 
18float GetAreaOfCircle(float radius) {
19	return radius * radius;
20}
21int main() {
22	float area = 3.14f * GetAreaOfCircle(3.0f);
23	printf("%d", );
24    getch();
25    return 0;
26}