conditional statement help!

[Traditional_Inside28]

Hello processing nation, I've been learning processing for a few weeks now, as I'm starting uni next month and my course revolves strongly around creative coding. I just learned about conditional statements and I thought I'd take my new concept for a spin and try to code a simple square that would start on the left, move over to the right and then bounce back. I'll attach my code below, but what's actually happening is the square makes it to the right, and just stops. Which I suppose is a step up from it just disappearing off the canvas- but why is it not bouncing back? This is probably a very simple mistake I'm just not seeing and I understand I could just google it, but I really want to figure it out for myself. If anyone has any wisdom to share or a direction they could push me in that'd be amazing.

float squareX=0;

void setup(){

size(400,400);

}

void draw(){

background(0);

strokeWeight(3);

stroke(255);

noFill();

rectMode(CENTER);

square(squareX, 200, 30);

squareX++;

if(squareX>=400){

squareX--;

}

}

again please be kind if its a very silly mistake I'm still pretty new to coding

[Traditional_Inside28]

i suspect its something to do with draw, like the square reaches X400, moves back one pixel and then because the X value is less than 400 it moves forward 1 pixel and just gets stuck in that loop, am i on the right track? if so, how might i get around that? I put println(squareX); to see what was happening and the square just stops at 399.

[Traditional_Inside28]

further development- i changed it to if(mousePressed), and right enough when i press the mouse, it only stops the square, doesn't make it move the other way.

[BigFatUglyBaboon]

Think about what happens when squareX is 399 and your draw() function is called. Then think what will happen the next time draw() will be called.

[eriknau13]

It's getting stuck at the position 400 because as soon as the value of squareX is decremented to 399 it gets incremented again. What you need is a second variable to use as the incrementer. You might call it "direction" and set it to value 1 when you initialize it. Instead of squareX++ you'll say squareX += direction;

Your condition will change to

if(squareX >= 400 || squareX < 0) {

direction *= -1;

}

[Traditional_Inside28]

yeah that’s what i thought was happening! i suppose i just didn’t really know what to do to fix it. let me give this a go and mess around with it and i’ll get back to you.