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Topic: Multi Dimensional Arrays (Read 521 times) |
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GotCool
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Multi Dimensional Arrays
« on: Aug 5th, 2004, 6:25pm » |
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How would I do some thing like this:
var myArray = [["Jim", "cars"], ["Sally", "bikes"], ["Ron", "movies"]];
in Processing?
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TomC
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Re: Multi Dimensional Arrays
« Reply #1 on: Aug 5th, 2004, 6:37pm » |
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You can do it like this:
Code:
String myArray[][] = { {"Jim", "cars"}, {"Sally", "bikes"}, {"Ron", "movies"} };
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Which is actually shorthand for this:
Code:
String[][] myArray = new String[][] { new String[]{"Jim", "cars"}, new String[]{"Sally", "bikes"}, new String[]{"Ron", "movies"} };
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Incidentally, in Java the following two ways of declaring arrays are equivalent, so use the one which makes most sense to you.
Code:
String myArray[][];
String[][] myArray;
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| « Last Edit: Aug 5th, 2004, 6:39pm by TomC » |
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GotCool
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Re: Multi Dimensional Arrays
« Reply #2 on: Aug 5th, 2004, 7:02pm » |
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Thanks!
There must be something else wrong with my code:
Code:
void setup() {
size(600, 400);
background(255);
ellipseMode(CENTER_DIAMETER);
noStroke();
fill(0);
smooth();
}
float radius=25;
float gravity=2;
float friction=.8;
float balls=2;
int ball[][];
for (int i=0; i<balls; i++) {
boolean hit=true;
while(hit) {
int x=random(radius, width-radius);
int y=random(radius, height-radius);
hit=false;
for (int j=0; j<i; j++) {
if (dist(x, y, ball[j][0], ball[j][1]) < 2*radius) {
hit=true;
}
}
}
ball[i] = {x, y, 0, 0};
}
void loop() {
background(255);
for (int i=0; i<balls; i++) {
ellipse(ball[i][0], ball[i][1], 2*radius, 2*radius);
}
}
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It's supossed to create balls with individual properties to be later used and changed. Where did I go wrong?
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arielm
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Re: Multi Dimensional Arrays
« Reply #3 on: Aug 5th, 2004, 8:22pm » |
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the problem is here:
ball[i] = {x, y, 0, 0};
this form is only possible when declaring an array variable, while here: you use it in the middle of your code...
solution: standard array access, e.g.
ball[i][0] = x;
ball[i][1] = y;
etc...
note: all this is over-complicated anyway (looks like c code), but in java, you can take advantage of object-oriented programming for such stuff.
here's a processing tutorial staring o.o.p and balls:
http://p5.chronotext.org/tutorials/motion_oop/
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Ariel Malka | www.chronotext.org
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GotCool
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Re: Multi Dimensional Arrays
« Reply #4 on: Aug 5th, 2004, 9:38pm » |
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Much thanks again, I got it working =)
Code:
Ball[] balls;
void setup() {
size(600, 400);
ellipseMode(CENTER_DIAMETER);
noStroke();
noSmooth();
balls = new Ball[100];
for (int i=0; i<balls.length; i++) {
balls[i] = new Ball();
boolean hit=true;
while(hit) {
balls[i].x=random(radius, width-radius);
balls[i].y=random(radius, height-radius);
hit=false;
for (int j=0; j<i; j++) {
if (dist(balls[i].x, balls[i].y, balls[j].x, balls[j].y) < 2*radius) {
hit=true;
}
}
}
balls[i].f = 40+random(40);
}
}
float radius=10;
float gravity=2;
float friction=.9;
void loop() {
background(120, 140, 100);
for (int i=0; i<balls.length; i++) {
balls[i].refresh();
}
}
class Ball {
float x;
float y;
float xSpeed=random(-20, 20);
float ySpeed=0;
float f;
void refresh() {
x+=xSpeed;
y+=ySpeed;
if (x-radius<0) {
x=radius;
xSpeed*=-friction;
ySpeed*=friction;;
}
if (x+radius>width) {
x=width-radius;
xSpeed*=-friction;
ySpeed*=friction;;
}
if (y-radius<0) {
y=radius;
xSpeed*=friction;
ySpeed*=-friction;;
}
if (y+radius>height) {
y=height-radius;
xSpeed*=friction;
ySpeed*=-friction;;
}
fill(f-20, f, f-40);
ellipse(x, y, 2*radius, 2*radius);
ySpeed+=gravity;
}
}
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| « Last Edit: Aug 5th, 2004, 10:06pm by GotCool » |
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narain
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Re: Multi Dimensional Arrays
« Reply #5 on: Aug 6th, 2004, 3:07pm » |
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Quote: ball[i] = {x, y, 0, 0};
this form is only possible when declaring an array variable, while here: you use it in the middle of your code... |
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You can, in fact, use something like this "in the middle of your code"; the syntax is
ball[i] = new int[] {x, y, 0, 0};
because Java needs to be told to create a new array to assign ball[i] to.
(In declarations, it knows it has to create one anyway, so no need, though you can probably use this syntax there as well.)
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