Add variable to an array index

Joris

Hi all!

First of all, i'm new to java so please forgive me for easy questions and my bad English (I'm Dutch).

I have a code with an array: robotStartX[], the x position of a robot. I would now like to add the value of a variable to one of the indexes of robotStartX[].

Why doesn't the following work?

int robotStartX[] = new int[4];
int value = 12;

robotStartX[1] += value;
println(robotStartX[1]);

Could someone please tell me how to do this?

Thanks!

Joris van Lanen

GoToLoop

It prints out 12. I don't get why you're claiming it's not working? (:|

koogs

also note: array indexes start at 0 so robotStartX[1] is actually the second after robotStartX[0] (but perhaps you know this)

Joris

Oke thanks, I made a new simple one to test it out:

int robotStartX[] = new int[4];
int value = 12;

void setup() {
  size(200,200);

}


void draw() {
  frameRate(2);


     for (int i = 0; i < 4; i++) {
       background(0);
robotStartX[i] += value;
rect(robotStartX[1],20,20,20);

     }
}

It indeed works fine, but for some reason it doesn't work with my other code. I'll just paste it here. There might me some Dutch words, sorry for that!

int value;

void setup() {
  size(400, 400);
  background(0);
}

void draw() {
  frameRate(6);
  background(0);
  tekenRobots();
}

void tekenRobots() {
  int robots = 4;
  int robotStartY = 80;
  int[] robotStartX = new int[robots]; 

  for (int i = 0; i < robots; i++) {


    dobbel(); 
    value = dobbel();
    robotStartX[i] += value; 


    println("value: " + value);
    //println("i= " +i);
    println("X: " + robotStartX[i]);

    fill(0, 0, 255);  
    stroke(0, 0, 255);
    triangle(robotStartX[i], robotStartY, robotStartX[i]+30, robotStartY, robotStartX[i]+(30/2), robotStartY-30); 
    fill(0);
    text(i+1, robotStartX[i]+30/3, robotStartY); 
    robotStartY += 80; 
  }
}

int dobbel() {
  int dices = 3;
  if (dices == 1) { 
    int dobbel1 = int(random(1, 7)); 
    int value = dobbel1;
    return value; 
  }
  else if (dices == 2) { 
    int dobbel1 = int(random(1, 7));
    int dobbel2 = int(random(1, 7)); 
    int value = dobbel1+dobbel2;
    return value;
  }
  else { 
    int dobbel1 = int(random(1, 7));
    int dobbel2 = int(random(1, 7));
    int dobbel3 = int(random(1, 7));
    int value = dobbel1+dobbel2+dobbel3;
    return value;
  }
}

The robots should be going further to the right because the X is being raised, but it doesn't......

Thanks

PhiLho

tekenRobots() re-create the array of robots on each frame, the previous one is lost.

I think you want to define robotStartX as a global variable.

See also the What are setup() and draw()? article.

Joris

Thanks very much!!! It works now! I indeed only had to move the create array statement to a place where it's not being done over and over again. Thanks again, problem SOLVED! :)