[Hall] Unit 8 JS Variables & Animation

Which is an example of declaring a variable?

• var sunSize = 10;

• sunSize = 10;

• sunSize;

• sunSize += 10;

Answer explanation

In JavaScript we use

var

to declare a variable.

Where is our PDE file do we declare a varaible?

• outside of the draw function

• inside of the draw function

Answer explanation

For now, all variables we use in the PDE file should be declared OUTSIDE of the draw function.

Sample Syntax~~

setup function

DECLARE VARIABLES

draw function

Which is an example of incrementing a variable?

• var sunSize = 10;

• sunSize = 10;

• sunSize += 10;

Answer explanation

To increment a variable means to increase it by the same amount at each change.

For example, your code may increment a scoring variable by +2 each time a goal is made.

Which is the shortcut version of

toothSize = toothSize + 8;

• toothSize += 8;

• toothSize + 8;

• toothSize = 8;

• toothSize ++ 8;

Which is the shortcut version of

toothSize = toothSize - 3;

• toothSize -= 3;

• toothSize - 3;

• toothSize = 3;

• toothSize -- 3;

Where is our PDE file do we increment a variable?

• outside of the draw function

• inside of the draw function

Answer explanation

For now, all variables we increment in the PDE file should be declared INSIDE of the draw function.

How many time do we need to declare each variable?

example

var xPosition;

• Once

• Every time we use the variable

What code is equivalent to

boatXPos += 1

• boatXPos ++;

• boatXPos --;

• boatXPos +;

• boatXPos -;

What code is equivalent to

boatXPos -= 1

• boatXPos ++;

• boatXPos --;

• boatXPos +;

• boatXPos -;

What is an example of camel case?

• eyeSize

• EyeSize

• eye_size

• eyesize

Answer explanation