Unit Circle Animation setting X as 1 three times instead of 1

Question

I'm doing a project about the unit circle and decided to code a visual representation in Java Processing, however when testing the code displays as the X value being 1 three times even though it's in the list of X values one time. Any ideas as to why?

Code:

float r = 300;
float[] xs = {1, sqrt(3/2), sqrt(2)/2, .5,        0, -.5,      -sqrt(2)/2, -sqrt(3)/2, -1, -sqrt(3)/2, -sqrt(2)/2, -.5,         0, .5,          sqrt(2)/2, sqrt(3/2)};
float[] ys = {0, .5,        sqrt(2)/2, sqrt(3)/2, 1, sqrt(3)/2, sqrt(2)/2, .5,          0, -.5,        -sqrt(2)/2, -sqrt(3)/2, -1, -sqrt(3)/2, -sqrt(2)/2, -.5};

void setup() {
  size(900, 900);
  background(0);
  noFill();
  stroke(255);
  strokeWeight(4);
  textAlign(CENTER, CENTER);
}

void draw() {
  background(0);
  translate(width / 2, height / 2);
  circle(0,0,r * 2);
  for (int i = 0; i < xs.length; i++) {
    line(0, 0, xs[i] * r, ys[i] * r);
  }  
}

Answer 1

The reason you are getting these erroneous values (as Joop Eggen pointed out) is that you're using integer division in some of your values:

float[] xs = { ... sqrt(3/2) ... sqrt(3/2)};

Change these to the following and it should resolve your issue:

float[] xs = { ... sqrt((float) 3/2) ... sqrt((float) 3/2)};

All the other calculations perform float division, so no need to adjust them particularly. Full code with these changes applied:

float r = 300;
float[] xs = {1, sqrt((float) 3/2), sqrt(2)/2, .5,        0, -.5,      -sqrt(2)/2, -sqrt(3)/2, -1, -sqrt(3)/2, -sqrt(2)/2, -.5,         0, .5,          sqrt(2)/2, sqrt((float) 3/2)};
float[] ys = {0, .5,        sqrt(2)/2, sqrt(3)/2, 1, sqrt(3)/2, sqrt(2)/2, .5,          0, -.5,        -sqrt(2)/2, -sqrt(3)/2, -1, -sqrt(3)/2, -sqrt(2)/2, -.5};

void setup() {
  size(900, 900);
  background(0);
  noFill();
  stroke(255);
  strokeWeight(4);
  textAlign(CENTER, CENTER);
}

void draw() {
  background(0);
  translate(width / 2, height / 2);
  circle(0,0,r * 2);
  for (int i = 0; i < xs.length; i++) {
    line(0, 0, xs[i] * r, ys[i] * r);
  }  
}