Lesson 13: Variables (computer science notes/review)

computer science notes/review

variable definition

named container for storing data

____ is stored in RAM, so it is volatile

variable

variable is stored in _____, so it is volatile

RAM

Variable is used to store info to be _____/______

referenced/manipulated

____ make code reusable/dynamic

variable

How do you do camelCase?

1st var letter lowercase

2nd var word uppercase

Variables cannot start with a _____ or _______.

number ; special character

Why should names be descriptive & consistent?

so you & other ppl understand it

Use ‘let’ when ___________.

variables can be reassigned

use ‘const’ when _______

variables CANNOT be reassigned

Avoid using var because its _____ and ______

function-scoped; older

Global scope definition

access anywhere in code

Avoid ___ Scope for functions

Global Scope

What are cons of Global Scope?

wide use—> forget what code does —> bugs

Local Scope definition

declared inside functions/blocks

Block Scope definition

declare variable within blocks/functions

RW: What keyword should you use to declare a variable that can be changed?

‘let’ keyword

RW: True or False: The following variable name is valid in JS: 6shooter

False; invalid b/c begins with # instead of letter

RW: True or False: A “const” variable must be initialized when declared.

True; you have to give it a value right away or it wont work