- Object - a software bundle of related state, and behavior that are used to model the real-world objects.
- Real-world objects - all have state and behavior.
- Object-oriented programming - is treated like a real-world object, and have a state and behavior.
- An object stores its state in fields and exposes its behavior through methods.
- Methods - operate on an object's internal state and serve as the primary mechanism for object-to-object communication.
- Benefits of bundling code:
- Modularity - source code for an object can be written and maintained independently of the source code for other objects
- Information-hiding
- Code re-use
- Pluggability and debugging ease
- Class - a blueprint or prototype from which objects are created, and are models the state and behavior of a real-world object
- The fields represent the object's state, and the methods define its interaction with the outside world.
Classes
- Sample code for a possible implementation of a class:
- First declare the public class, then put the three fields in the public class.
- Underneath the fields put the constructor for the class.
- Underneath the constructor put the methods that you want the class to have.
- Sample code for a possible implementation of a subclass
- Declare the subclass of the class first.
- Then give the subclass a field, constructor, and a method.
Binary, Decimal and Hexadecimal Numbers
- Decimals - Every digit in a decimal number has a position, and the decimal point helps us to know which position is which.
- Bases - Base 10 or the Decimal Number System is based on the number 10.
- Counting with Different Number Systems - Count up until just before the "Base Number", then start at 0 again, but first you add 1 to the number on your left.
- Binary Numbers - are just "Base 2", which means you can onlt start counting at 0 and then 1.
- Hexadecimal Numbers - has 16 numbers, which look the same as the decimal numbers up to 9. After 9 there are the letters A - F in the place of decimal numbers.