我应该如何确定可将苹果放置在特定位置？

Question

function Apple() {
  this.x = 0;
  this.y = 0;

  this.show = function() {
    fill(255, 0, 0);
    noStroke();
    rect(this.x, this.y, scl, scl);
  }

  this.create = function() {
    var cols = fieldWidth/scl;
    var rows = fieldHeight/scl;

    do {
      this.x = floor(random(cols))*scl+15;
      this.y = floor(random(rows))*scl+30;
    } while (!empty());

  }

  function empty() {
    for (var i = 0; i < s.body.length; i++) {
      if (this.x == s.body[i].x & this.y == s.body[i].y) {
        return false;
      }
    }
    return true;
  }
}

this is the code for the apple object in my snake game. the empty() function is used to ensure the apple doesn't spawn inside of the snake in the create() function. at the moment it does not work how would i fix it?

Answer 1

I believe that you mistyped the Logical AND operator. You should use && instead of &

Here is how your code should be:

function Apple() {
  this.x = 0;
  this.y = 0;

  this.show = function() {
    fill(255, 0, 0);
    noStroke();
    rect(this.x, this.y, scl, scl);
  }

  this.create = function() {
    var cols = fieldWidth/scl;
    var rows = fieldHeight/scl;

    do {
      this.x = floor(random(cols))*scl+15;
      this.y = floor(random(rows))*scl+30;
    } while (!empty());

  }

  function empty() {
    for (var i = 0; i < s.body.length; i++) {
      if (this.x == s.body[i].x && this.y == s.body[i].y) {
        return false;
      }
    }
    return true;
  }
}