Unit 1: Primitive types

Intro to OOP

• Read the introduction to object-oriented programming (OOP) here.

Intro to Java:

• Read the following article on Java.

The "Hello world" program:

Follow the steps in this tutorial to create your first Java program in the BlueJ programming environment.

Q: What is the difference between the print() and println() methods?

Read the unit on Java class, methods and instance variables

Variables and data types

Primitive vs. reference data types:

• primitive data types - The memory associated with these stores the actual data
• reference data types - the memory associated with these only stores a pointer to the actual data (e.g. String)

AP Java subset primitive types:

int, double, and boolean (not the char type)

The int type:

Watch this video first

Then watch the video on the int data type operations

Pseudo-constants / "Final" variables:

"final" keyword

e.g.: final double VAT_RATE=19.0

expressions and assignment statements

• a literal: the source code representation of a fixed value
• arithmetic operators: +, -, *, /, %
• two int values evaluate to an int value
• an operation including a double will evaluate to a double value
• compound expressions: e.g. (a+b)/c
• operator precedence
• division of an int by zero -> ArithmeticException
• "=" the assignment operator, e.g. a=55 (what is on the right is stored in a variable named on the left)
• expressions are evaluated to produce a single value during execution

order of operations:

1. !, ++, --
2. *, /, %
3. +, -
4. <,>,<=,>=
5. ==,!=
6. &&
7. ||
8. =, +=, -=, *=, /=, %=

Operators of equal precedence are invoked from left to right (except for the first and last line where it's from right to left). Casting takes place first. Parentheses have precedence over arithmetic operators.

compound assignment operators

• Compound assignment operators: +=, -=,*=,/=,%=
  • "a+=1" reads as "a=a+1", etc.
• Increment operator: ++ ( plus one)
• Decrement operator: -- (minus one)

Q: Do the increment/decrement operators work in Python?

casting and ranges of variables

Read the w3schools entry on primitives casting in Java

Q: What is the equivalent of casting in Python?