Array very basic assignment question

PlzHelp

float[] s = new float[width];
float sx = 20;

for (int i = 0; i < width; i+= sx) {
    s[i] = i;
}

for (int i = 0; i < s.length; i++) {
    ellipse(s[i],20,20,20);
}

this will work will show 5 circles

but then why if i put that inside draw() or setup() it give an ArrayIndexOutofBoundsException:0

float[] s = new float[width];

void setup(){
}

void draw(){
  float sx = 20;
  for (int i = 0; i < width; i+= sx) {
    s[i] = i;
  }
  for (int i = 0; i < s.length; i++) {
    ellipse(s[i],20,20,20);
  }
}

ArrayIndexOutofBoundsException:0

GoToLoop

http://forum.processing.org/two/discussion/8045/how-to-format-code-and-text

• 1st code uses the "immediate" mode. It got no setup() nor draw() and no other defined functions.
• 2nd code is a regular full sketch. It got at least 1 setup() or 1 draw() or both.
• System vars width, height & sketchPath aren't still initialized until code reaches setup() though.
• Therefore at float[] s = new float[width];, s[] is an array of length = width = 0! @-)

_vk

width is not known until setup() is run, unless there is no setup() then the pre processor will run a basic default setup() behind the scene setting width to 100. Thus your first code works

When you add setup() and don't specify a size() it will set width to 100 as well, but it can't be accessed before setup(), so

float[] s = new float[width];// width is 0 here...
void setup(){}

That line before setup will fail to properly initialize the array, hence the "OutOfBounds"

You can split declaration and initialization to make this work, like:

float[] s  ;//declare global so can be accessed in draw

void setup() {
  s = new float[width];//init after width has a value
}

void draw() {

  float sx = 20;
  for (int i = 0; i < width; i+= sx) {
    s[i] = i;
  }
  for (int i = 0; i < s.length; i++) {
    ellipse(s[i], 20, 20, 20);
  }
} 

_vk

ops... late :)

PlzHelp

welp,thats a no brainer have not thought about it thanks