From last time…• Libraries, Functions, Active Mode, Interaction!

• Check the site for a list of inspiration sources!

• We have a Teaching Assistant:!

! Yifan Wang, yifan@cise.ufl.edu!

! Office Hours: CSE309, 2:00pm–3:00pm

CAP 3032

Variables

What is a variable?• An address in memory: 0x0000883A!

• Variables have a type and a name! int x; int y; float weight; string introduction;

Memory

int x;

The Primitivesboolean!! ! true or false!char! ! ! ! ‘a’ ‘b’ ‘c’!byte! ! ! ! -128 to 127 short! ! ! -32,768 to 32,767!int ! ! ! -2147483648 to 2147483647!long! ! ! ! larger numbers!!float! ! ! 3.14159!double! ! ! float with more decimal places

Common Primitives

boolean!! ! true or false!int ! ! ! -2147483648 to 2147483647!float! ! ! 3.14159

Using Variables

1. Declare the variable! int xposition; // type name;

2. Initialize the variable! xposition = 10; // name = value;

Using Variables

1 & 2. Declare & Initialize the variable! int xposition = 10; // type name = value;

Demo Variables

System VariablesmouseX, mouseY

pmouseX, pmouseY

width, height // sketch dimensions

frameCount, frameRate

displayWidth, displayHeight // screen dimensions

key, keyCode, keyPressed

mousePressed // is it pressed?

mouseButton // left/center/right

Demo!System Variables

random() & castingrandom(j) // from 0 to j

random(j,k) // from j to k

float r = random(24);

int r = random(24); // needs to be cast!

int r = int(random(24)); // int() method

int r = (int) random(24); // Java cast

For next time…• Monday is Martin Luther King, Jr. Day!

• Read Shiffman, p. 59–70 (Conditionals I)!

• Project Proposals due on Wed, January 22

Quiz• Closed book, 25 minutes, good luck!