AP CSA Unit 1: Lesson 2 - User Input and Variables

Scanner

allows us to take user input and incorporate it into our programs

variables

containers in memory

declare

when we declare a variable, we tell the computer to allocate some space in memory for something

initialize

when we first put a value in the container we initialize the variable

assignment operator

equals sign (=)

naming variable rules

We can only use letter/number characters and the special characters _ and $. No spaces or other characters are allowed.
Your variable can't start with a number (so num1 is ok as a variable name but 1num is not).
You can't use names which already have a meaning in Java (e.g. we can't name our variable String or System).

concatenation

when we glue strings together using a plus sign

comments

useful for writing a reminder of what code does, leaving ourselves a to-do list, or for isolating a problem while debugging