1. From last time…
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Libraries, Functions, Active Mode, Interaction!
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Check the site for a list of inspiration sources!
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We have a Teaching Assistant:!
! Yifan Wang, yifan@cise.ufl.edu!
! Office Hours: CSE309, 2:00pm–3:00pm

2. Variables
CAP

3. What is a variable?
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An address in memory: 0x0000883A!
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Variables have a type and a name!
int x;
int y;
float weight;
string introduction;

4. Memory
int x;

5. The Primitives
boolean!! ! 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

6. Common Primitives
boolean!! ! true or false!
int ! ! ! -2147483648 to 2147483647!
float! ! ! 3.14159

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

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

9. Demo Variables

10. System Variables
mouseX, mouseY
pmouseX, pmouseY
width, height
// sketch dimensions
frameCount, frameRate
displayWidth, displayHeight
dimensions
// screen
key, keyCode, keyPressed
mousePressed
// is it pressed?
mouseButton
// left/center/right

11. Demo!
System Variables

12. random() & casting
random(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

13. For next time…
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Monday is Martin Luther King, Jr. Day!
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Read Shiffman, p. 59–70 (Conditionals I)!
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Project Proposals due on Wed, January 22
Quiz
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Closed book, 25 minutes, good luck!