This document discusses variables in coding and provides examples of their use. It introduces different data types for variables like integers, floats, characters, and booleans. It demonstrates how to assign values to variables and how variables can be used in expressions and statements. Special processing variables like size, background, mouseX and mouseY are described for creating dynamic sketches. The document concludes with an exercise to create an interactive line composition using variables.

1. Crea%ve
Coding
Interac%on
Design
Lab
1,
IUAV,
WS
10/11
Till
Nagel,
FH
Potsdam,
10/2010

2. Variables

3. Variables:
Data
types
int
count
=
0;
float
score
=
43.71;
char
letter
=
'a';
boolean
niceWeather
=
true;

4. Variables:
Assign
values
int
x
=
0;
line(x,
10,
x,
200);
x
=
50;
line(x,
10,
x,
200);

5. Variables:
Assign
values
int
x
=
0;
//
ok
int
y
=
0.3;
//
error:
float
value
z
=
10;
//
error:
not
declared
char
c
=
true;
//
error:
wrong
type

6. 1
+
2
+
3
+
4
+
5
=
?
1
+
2
3
+
3
6
+
4
10
+
5
=
15

7. Variables:
Usage
int
sum
=
0;

8. Variables:
Usage
int
sum
=
0;
sum
=
1
+
2;

9. Variables:
Usage
int
sum
=
0;
sum
=
1
+
2;
sum
=
sum
+
3;

10. Variables:
Usage
int
sum
=
0;
sum
=
1
+
2;
sum
=
sum
+
3;
sum
=
sum
+
4;
sum
=
sum
+
5;

11. Variables:
Usage
int
sum
=
0;
sum
=
1
+
2;
sum
=
sum
+
3;
sum
=
sum
+
4;
sum
=
sum
+
5;
println(sum);

12. Expressions
int
a
=
3;
int
b
=
5;
int
c
=
a
+
b;
a
=
b
*
2;
c
=
c
+
a;

13. Expressions
in
statements
int
x
=
100;
int
y
=
20;
fill(x);
line(x,
y,
300,
y
*
2);

14. Special
Processing
variables

15. Sta%c
sketch
size(200,
200);
background(0);
line(100,
50,
0,
0);
ellipse(100,
100,
20,
20);

16. Dynamic
sketch
void
setup()
{
size(200,
200);
background(0);
}
void
draw()
{
line(100,
50,
0,
0);
ellipse(100,
100,
20,
20);
}

17. Dynamic
sketch
void
setup()
{
size(200,
200);
background(0);
}
void
draw()
{
line(100,
50,
mouseX,
mouseY);
ellipse(mouseX,
mouseY,
20,
20);
}

18. Excersises
E4:
Create
a
dynamic
interac.ve
line
composi.on.

19. Thank
you.
Copyright
Till
Nagel,
FH
Potsdam,
10/2010