Java file = all of our code .md file = text, definitions, etc.

Intro to Java

A Java program can be characterized as an object represented in a class Currently our program has a Main object. Inside of this object we have the Main class.

Output

In Java to Output an item to the console we use: 'System.out.print()' and 'System.out.println()' System.out.println() prints the statement and moves to the next line, while System.out.print() just prints the statement.

Comments

A comment is used as user annotation with the purpose of being human readable. Line Comments follow double backslashes. // Block Comments are contained within /* Comments */

Identifiers

In Java use the term identifier to describe a variable, parameter, constant, user-defined method or user-defined class.

• Cannot begin with digit
• Can only contain letters, digits, and underscores
• Case-sensitive age != Age *Note: *
• class name starts with a capital letter
• reserved words are entirely lowercase and may not be used as identifiers (Reserved words will show up in blue)

Types

** Primitive** or built-in types in Java are

• int An integer
• boolean True or False (boolean shirtColor = true)
• double floating-point number (2.73)
• char single character

*Note: *Integers have a fixed amount of memory, so there is a limit to how many digits you can store(2^31-1)

Variables

Variables are a type of identifier that stores a value of a specific type

We can create variables using declaration

• int age;
• double x, y;
• boolean found; -char letter; We can also initialize a variable in its declaration
• int count = 1;
• double p = 3.14;
• char c = '8';

Chars

[Ascii Chart] (https://docs.google.com/document/d/1oubLTqAHmdkadtjbR8xxREG7auvuUqiQ/edit)

Each character is associated with an ASCII value.

Type Cast

One type can be cast to another compatible type if appropriate

char letter = 'c'; int value = (int)letter;