Rectangle coding help

Processing Coding Questions
1 
int numRows;
int rowColumns;
int rowLength;

int startX;
int startY;

int rectWidth;
int rectHeight;

boolean isColour;

void setup () {
  size (900, 400);
  stroke (0);
  numRows = 1;
  rowColumns = 1;
  rowLength = 10;
  startX = 50;
  startY = 350;
  rectWidth = 75;
  rectHeight = 30;
  isColour = false;
}

void draw() {
  background (155);
  
  while (numRows < rowLength) {
    rect (startX, startY, rectWidth, rectHeight); 
    startX = startX + rectWidth;
    numRows = numRows + 1; //adding this line breaks the code thus no rectangle is drawn??!)
    print(numRows + ", ");
  }
  
}

I want the rectangles to keep producing while numRows is less than rowLength. For some reason, after adding the numRows + 1; (i.e. the count), no rectangle is produced. What am I doing wrong here?

Thanks!
Before I add the numRows = numRows + 1 command

Capture
Capture898×375 1.91 KB

After I add the numRows = numRows + 1 command, there’s no rectangle being drawn

2

Hello,

Please format your code:
https://discourse.processing.org/faq#format-your-code

Is this a homework question or academic assignment?

You edited your last post to remove the code after it was solved:

:)

3

It’s a homework question. And apologies for that thread. I will not do that again.

4

Hello,

Your program is executing exactly the way you coded it. After the the first draw() loop (which has rectangles) the next loop falls through the while loop (10 is not < 10) and the canvas is cleared for each draw() cycle that follows.

I added a noLoop() to end of setup() so draw() only loops once and you can see output.
I also added some println() statements.

image
image618×681 34.6 KB

First cycle (frame) of draw():

image
image902×427 7.3 KB

After that background() clears canvas and it is grey.

Try initializing variables at start of draw before the while loop.

:)

1 Like
5

I understand now. Many Thanks!

1 Like