Java Slides

1. Classes & Object

2. • Represent the real world
BABY
Object oriented programming

3. • Represent the real world
Baby
Name
Gender
Weight
Decibels
# cry so far
Object oriented programming

4. • Objects group together
Primitives (int, double, char, etc..)
Objects (String, etc…)
Baby
String name
boolean isMale
double weight
double decibels
int numCry
Object Oriented Programming

5. • Why not just primitives?
// little baby ram
String nameRam;
double weightRam;
// little baby Sham
String nameSham;
double weightSham;
Why use classes?

6. • Why not just primitives?
// little baby ram
String nameRam;
double weightRam;
// little baby Sham
String nameSham;
double weightSham;
// little baby Sham2
String nameSham2;
double weightSham2;
Why use classes?
500 Babies? That’s Confusing!!!

7. Why use classes?
Name
Gender
Weight
……
BABY1

8. Name
Gender
Weight
……
BABY1
Name
Gender
Weight
……
BABY2
Name
Gender
Weight
……
BABY3
496 more
Babies…..

9. Baby1 Baby2 Baby3
Nursery
Why use classes?

10. public class Baby {
String name;
boolean isMale;
double weight;
double decibels;
int numCry = 0;
void cry() {
numCry += 1;
System.out.println(“Dear mother, ”+
“Please look why I am crying??”);
} }
Class -overview
Class Definition

11. Baby myBaby = new Baby();
Class -overview
Class instance

12. •Class names are Capitalized
•1 Class = 1 file
•Having a main method means the class can be run
Note

13. public class CLASSNAME{
CLASSNAME ( ) {
}
CLASSNAME ([ARGUMENTS]) { }
}
CLASSNAME obj1 = new CLASSNAME();
CLASSNAME obj2 = new CLASSNAME([ARGUMENTS])
Constructors