1. Introduction to Programming using Java
Day 5 and 6
Review
The “String” class
Objects!

2. Review Variables Control If-then-else Loops Subroutines
The String class

3. Subroutine Review public class HelloWorld {
public static double calculateArea(int radius){
double x;
System.out.println("inside calculateArea, radius: " + radius);
x = 3.14 * radius * radius;
return x; }
public static void main(String[] args) {
System.out.println("Hello World from Robot laptop");
double sheehyArea = calculateArea(6);
System.out.println("my area was: " + sheehyArea);
sheehyArea = calculateArea(10);

4. The String Class you can do operations on a String object!!
String myName = “Mr. Sheehy”;
System.out.println(
“length: “ + myName.length());
“uppercase: + myName.toUpperCase());

5. String Review public class HelloWorld {
public static void main(String[] args) {
String myString = new String(“Hello world from Robot laptop”);
System.out.println(myString);
String myOtherString = “Hello world from Robot laptop”);
System.out.println(myOtherString); }

6. The Java API

7. Task 1 declare and initialize a String object
initialize it to your full name
using the java api
get a new String that is a substring of your name
the new String should be only your middlename

8. Demo
outbound calling program

9. Objects an abstract notion. a way to encapsulate. classes objects
fields
methods
public and private

10. Task 2 create a class for some kind of animal
your class must have at least 2 data fields
your class must have a constructor
your class must have at least 2 methods
in your main(), declare and initialize an object with your classes type
make your object do something

11. Review for day 6 class layout classes versus objects revisit methods
return types
how to declare a method

12. Day 6 new topics public and private class members
new advanced topic: inheritance
you are almost ready!

13. Public and Private every member of a class is either public or private
you pick what to set it to based on what you want to expose to people who use the class
encapsulation!

14. Inheritance a class may “extend” another class which means
the subclass has everything that the base class has
the subclass IS the base class
but not the other way around
you can override how the base class acts

15. Task 3 using your object from last night
create another class that extends your class
for example, if you have a Dog class, then your subclass could be Poodle
make sure your subclass passes the IS-A test:
a Poodle is a dog, but a dog isn't necessarily a Poodle
add another method to your subclass to make your new class do something your base class can't do

16. Next Time
review
Robocode