Git + IntelliJ

A Java program

Printing

Variables + Types

User Input 

If Statements

standard workflow

Java

= a programming language + platform

platform

= an environment for running other programs

Java platform

• JVM
• Java language + compiler
• Java standard libraries

JVM

Java Virtual Machine

(virtual computer)

compiler

= a program that transforms source code into

machine code

in IntelliJ!

HelloWorld.java

variables

= names associated with values in a computer

variables allow programmers to save data and reference it later

naming variables

• case sensitive
• any length of letters and/or digits
• must begin with letter, "$", "_"
• by convention begin with a letter 
• whitespace is not permitted
• by convention are camelCase
• should be descriptive!!!

Primitive Types

every variable in Java has a type

Type

= a set of values and operations on those values

8 primitive types

• byte (8-bit integer)
• short (16-bit integer)
• int (32-bit integer)
• long (64-bit integer)
• float (32-bit floating point number)
• double (64-bit floating point number)
• boolean (true or false)
• char (a single character like '$' or 'a')

boolean

true or false

boolean operators

• >
• >=
• <
• <=
• ==
• !=

char

= represents a single character ('a', '$', '9')

denote a char by placing it between single quotes ' '

String

(not a primitive type)

= sequence of characters denoted by double quotes

concatenation

= the operation of joining strings together

ex. "Hello, " + "World!";

using Scanner

Scanner

Scanner methods

• next()
• nextByte()
• nextShort()
• nextInt()
• nextLong()
• nextFloat()
• nextDouble()
• nextBoolean()

Conditional Statements

= control structure

if (7 > 3) {
    System.out.println("Math is real");
}
System.out.println("This always executes");

if

if (7 > 3) {
    System.out.println("Math is real");
} else {
    System.out.println("Math is a lie");
}
System.out.println("This always executes");

if else

// aq is at the cinema
if (age <= 13) {
    ticketPrice = 8;
} else if (age <= 64) {
    ticketPrice = 13;
} else {
    ticketPrice = 10;
}

else if