Array index out of bounds question

Processing Coding Questions
1

What’s causing the ArrayIndexOutOfBoundsException: 5?
I want to make each bounce have a function that increases the value of the counter per ball. If the counter is greater than 10, stop drawing the ball

int bounces = 5;
float[] x = new float [bounces];
float[] y = new float [bounces];
float[] xspeed = new float[bounces];
float[] yspeed = new float[bounces];
int[] types = new int[bounces];
boolean alive = true;
color c;

color bgc;

void setup()
{

size(700, 700);
noStroke();
for (int i = 0; i < bounces; ++i)
{
x[i] = random(width);
y[i] = random(height);
xspeed[i] = random(-5, 5);
yspeed[i] = random(-5, 5);
c = color(random(100, 255), random(100, 255), random(100, 255));
bgc = color(random(100, 255), random(100, 255), random(100, 255));
textSize(25);
textAlign(CENTER, CENTER);
}
}

void draw()
{
//fondo negro
background(bgc);

for (int i = 0; i < bounces; ++i)
{
moveEllipse(i);
bounceEllipse(i);
drawEllipse (i);
}
}

void moveEllipse(int id)
{
x[id] += xspeed[id];
y[id] += yspeed[id];
}

void bounceEllipse(int id)
{
if (x[id] < 0 || x[id] > width && bounces >9)
{
xspeed[id] *= -1;
bounces = bounces +1;
}
if (y[id] < 0 || y[id] > height && bounces >9)
{
yspeed[id] *= -1;
bounces = bounces +1;
{
fill(0);
text(bounces, x[id], y[id]);
}
}
}

void drawEllipse(int id)
{
float xoff = (float)width / bounces;
fill(255);
ellipse(x[id], y[id], 50, 50);
}

2

Hi, @karenben please edit your code above by selecting it and pressing the </> button.
Without testing, I can see that you are increasing the value of the bounces, and at the same time calling the x[] and y[] array with this value higher than 5. This will give the ArrayIndexOutOfBoundsException error.

3

Hi @noel thanks for answering me! I have a problem. I don’t know what I did wrong but this is the exercise from the beginning. Now the number on the ball doesn’t appear anymore can you help me? I’m stuck
/ *

  1. Pass the exercise to logic of arrays and cycles for
  2. Each bounce will have a function that increases the value of the counter per ball.
  3. If the counter is greater than 10, stop drawing the ball
  4. When all the balls disappear print a message that says: “I love the code”
  • /

// initial variables for the ball
int bounces = 0;
float x = 0;
float y = 0;
float xspeed = 0;
float yspeed = 0;
boolean alive = true;
C color;

// variable for the background color
bgc color;

void setup ()
{
// we assign the dimensions of the canvas
size (700, 700);
// we assign that the ball will not have a stroke
noStroke ();
// we assign initial values ​​to the variables of the ball
x = random (width);
y = random (height);
xspeed = random (-5, 5);
yspeed = random (-5, 5);
c = color (random (100, 255), random (100, 255), random (100, 255));
// we assign initial values ​​for the background color
bgc = color (random (100, 255), random (100, 255), random (100, 255));
// we assign the font size of the letter
textSize (50);
// we justify the text vertically and horizontally centered
textAlign (CENTER, CENTER);
}

void draw ()
{
//black background
background (bgc);

// we increase the position of the object by its speed to achieve the illusion of movement
x + = xspeed;
y + = yspeed;

// logic for bouncing the ball
if (x <0 || x> width)
{
xspeed * = -1;
}
if (y <0 || y> height)
{
yspeed * = -1;
}

// we draw the ball
fill (255);
ellipse (x, y, 50, 50);
fill (0);
text (bounces, x, y);
}

//This is how I solved it:
/ *

  1. Pass the exercise to logic of arrays and cycles for
  2. Each bounce will have a function that increases the value of the counter per ball.
  3. If the counter is greater than 10, stop drawing the ball
  4. When all the balls disappear print a message that says: “I love the code”
  • /

// initial variables for the ball
int bounces = 10;
int ellipse = 5;
float [] x = new float [bounces];
float [] y = new float [bounces];
float [] xspeed = new float [bounces];
float [] yspeed = new float [bounces];
int [] types = new int [bounces];
boolean alive = true;
C color;

// variable for the background color
bgc color;

void setup ()
{
// we assign the dimensions of the canvas
size (700, 700);
// we assign that the ball will not have a stroke
noStroke ();
// we assign initial values ​​to the variables of the ball
for (int i = 0; i <ellipse; ++ i)
{
x [i] = random (width);
y [i] = random (height);
xspeed [i] = random (-5, 5);
yspeed [i] = random (-5, 5);
c = color (random (100, 255), random (100, 255), random (100, 255));
// we assign initial values ​​for the background color
bgc = color (random (100, 255), random (100, 255), random (100, 255));
// we assign the font size of the letter
textSize (25);
// we justify the text vertically and horizontally centered
textAlign (CENTER, CENTER);
}
}

void draw ()
{
//black background
background (bgc);

for (int i = 0; i <ellipse; ++ i)
{
moveEllipse (i);
bounceEllipse (i);
drawEllipse (i);
}
}

// we increase the position of the object by its speed to achieve the illusion of movement
void moveEllipse (int id)
{
x [id] + = xspeed [id];
y [id] + = yspeed [id];
}

// logic for bouncing the ball
void bounceEllipse (int id)
{
if (x [id] <0 || x [id]> width && bounces> 9)
{
xspeed [id] * = -1;
bounces = bounces +1;
}
if (y [id] <0 || y [id]> height && bounces> 9)
{
yspeed [id] * = -1;
bounces = bounces +1;
{
fill (0);
text (bounces, x [id], y [id]);
}
}
}

// we draw the ball
void drawEllipse (int id)
{
float xoff = (float) width / bounces;
fill (255);
ellipse (x [id], y [id], 50, 50);
}

4

Please try to edit your posts and format it with the code button. Once in a code box it can be easily copied with a button that appears above the vertical scrollbar.

5

@noel which is the code button?