为什么一个变量起作用，而另一个变量不起作用，而且两个变量非常相似

Question

https://editor.p5js.org/Meowmeow/sketches/b4AhGA4xH

这是使用 p5.js 的网络编辑器创建的。每当你用 j 做东西时，它都会有一个错误信息，除非你做 Cell =>。如果您使用 i 执行此操作，则不会出现错误消息。变量 i,j 在相同的地方被改变，除非我不小心做了什么。如果我这样做了，请指出，否则有人可以告诉我为什么会这样吗？

var cols, rows;
var diffeculty = 0;
var w = 50;
var grid = [];
var stack = [];
var current;
var check = []
var k = 0;
var m = 0;
var won = false;

function setup() {
  //frameRate(10)
  createCanvas(400, 400);
  cols = floor(width / w)
  rows = floor(height / w)


  for (var j = 0; j < rows; j++) {
    for (var i = 0; i < cols; i++) {
      var cell = new Cell(i, j)
      grid.push(cell)
    }
  }

  current = grid[0];
}
function index(i, j) {

  if (i < 0 || j < 0 || i > cols - 1 || j > cols - 1) {
    return -1;
  }
  return i + j * cols
}

function Cell(i, j) {


  this.visited = false;
  this.i = i;
  this.j = j;
  this.walls = [true, true, true, true];
  this.checkNeighbors = function() {
    var neighbors = []
    var top = grid[index(i, j - 1)]
    var right = grid[index(i + 1, j)]
    var left = grid[index(i - 1, j)]
    var bottom = grid[index(i, j + 1)]
    var Wall = this.walls;
    
    var wall=[]
    wall.push(i,j,Wall)
    
    
    if (top && !top.visited) {
      neighbors.push(top);
    }

    if (right && !right.visited) {
      neighbors.push(right);
    }
    if (bottom && !bottom.visited) {
      neighbors.push(bottom);
    }
    if (left && !left.visited) {
      neighbors.push(left);
    }

    if (neighbors.length > 0) {
      var r = floor(random(0, neighbors.length))
      return neighbors[r];
    } else {
      return undefined;
    }

  }

  this.highlight = function() {
    var x = this.i * w;
    var y = this.j * w;
    noStroke();
    fill(0, 0, 255, 100)
    rect(x, y, w, w);

  }
  this.show = function() {
    var x = this.i * w;
    var y = this.j * w;
    stroke(255);
    noFill();

    if (this.walls[0]) {
      line(x, y, x + w, y);
    }
    if (this.walls[1]) {
      line(x + w, y, x + w, y + w);
    }

    if (this.walls[2]) {
      line(x + w, y + w, x, y + w);
    }
    if (this.walls[3]) {
      line(x, y + w, x, y);
    }

    if (this.visited) {
      fill(255, 0, 255, 100);
      noStroke();
      rect(x, y, w, w);
    }
  }
};






function removeWalls(a, b) {
  var x = a.i - b.i;
  if (x === 1) {
    a.walls[3] = false;
    b.walls[1] = false;
  } else if (x === -1) {
    a.walls[1] = false;
    b.walls[3] = false;
  }
  var y = a.j - b.j;

  if (y === 1) {
    a.walls[0] = false;
    b.walls[2] = false;
  } else if (y === -1) {
    a.walls[2] = false;
    b.walls[0] = false;
  }


}

function draw() {
  background(51);
  for (var i = 0; i < grid.length; i++) {
    grid[i].show()
  }


  //Step One
  current.visited = true;
  current.highlight();

  var next = current.checkNeighbors()
  if (next) {
    next.visited = true;

    //Step 2
    stack.push(current);
    check.push(current)

    //Step 3
    removeWalls(current, next) 
    {}


    //Step 4 
    current = next;
  } else if (stack.length > 0) {
    current = stack.pop();

  }


  if (stack[0] === undefined) {
    fill(0, 105, 100)
    rect(0, 0, w, w)
    rect(width - w, height - w, w, w)
    frameRate(8)
  
    
   var c =  check.find(cell => cell.i == ~~(k/w) && cell.j == ~~(m/w));
    
    
    //console.log(c)
    

    
    
    if(c===undefined)
      {
        console.log(m,cell =>j)
        console.log(k,i)
      }
    
    if(keyIsDown(UP_ARROW)) {
      k -= w
    }
    if (keyIsDown(RIGHT_ARROW)) {
      m += w
    }
    if (keyIsDown(DOWN_ARROW)) {
      k += w
    }
    if (keyIsDown(LEFT_ARROW)) {
      m -= w
    }

    fill(0, 255, 255, 100)
    rect(m, k, w, w)

    if (m < 0) {
      m = 0
    }
    if (k < 0) {
      k = 0
    }
    if (m > width - w) {
      m = width - w
    }
    if (k > height - w) {
      k = height - w
    }

    if (k === height - w && m === width - w || won === true) {

      won = true
      background(0)
      textSize(40)
      text("You Win", width / 2, height / 2)
    }
  }

}

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Answer 1

问题与迷宫的生成有关。 check 数组中有些单元格出现两次，有些单元格丢失。您必须将 next 单元格而不是 current 单元格添加到数组中。当前单元格包含迷宫中的前一个位置：

function draw() {
    background(51);
    for (var i = 0; i < grid.length; i++) {
      grid[i].show()
    }

    var next = (stack.length == 0) ? grid[0] : current.checkNeighbors();
    if (next) {
        //Step One
        next.highlight();
        next.visited = true;

        //Step 2
        stack.push(next);
        check.push(next);

        //Step 3
        if (current && current != next)
            removeWalls(current, next);

        //Step 4 
        current = next;
    } else if (stack.length > 0) {
        current = stack.pop();
    }

    // [...]

为什么一个变量起作用，而另一个变量不起作用，而且两个变量非常相似

Why does one variable work, while the other one doesn't, and the two variables are very similiar

javascript

p5.js