Using for loop to print grid in JavaScript

Question

I am trying to create a small grid for connect four game using a four loop. I have printed circles for X and Y axis but I have only been able to print 1 row successfully, I am trying to print this seven times across the canvas but the for loop I have created does not seem to work.

var x = 30;

var y = 30; 

function setup(){

createCanvas(300,300);
background(0);

for(i=0; i<=6; i++){
    for(i=0; i<=6; i++){
        x+=30;
        circle(x, y, 20);
            for(i=0; i<=6; i++){
                y+=30;
                circle(x, y, 20);
        }
    }   
}
    }
    setup();

I am trying to achieve this:

Note: instead of for loops, you may consider using a pattern for this. — Kaiido
– Kaiido, Commented Apr 16, 2019 at 13:30

Jack Bashford · Accepted Answer · 2019-04-16 11:34:10Z

1

Change your loop structure - iterate 7 times and increase y at the end of each iteration, and iterate within this loop where you render the circle, and increase x:

for (let i = 0; i < 6; i++) {
    x = 30;
    for (let j = 0; j < 7; j++) {
        circle(x, y, 20);
        x += 30;
    }
    y += 30;
}

answered Apr 16, 2019 at 11:34

Jack Bashford

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Comments

Jonas Wilms · Accepted Answer · 2019-04-16 11:34:26Z

1

You do have three loops that use i, and actually all loops will work on the same number, therefore the inner loop will loop 6times, than all three loops end. As your aim is to loop over x and y, just use them:

  for(let x = 1; x < 6; x++) { // always declare variables with let!
    for(let y = 1; y < 6; y++) {
       circle(x * 30, y * 30, 20); // just keep as many varoables as necessary, the position can easily be derived from the index
    }
 }

answered Apr 16, 2019 at 11:34

Jonas Wilms

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Comments

enxaneta · Accepted Answer · 2019-04-17 07:46:31Z

Maybe this is what you need:

const canvas = document.getElementById("canvas");
const ctx = canvas.getContext("2d");
let cw = (canvas.width = 300),
  cx = cw / 2;
let ch = (canvas.height = 300),
  cy = ch / 2;
//the circles radius
let ar = 30;
//the red and yellow clees index
let red = [10, 23, 30, 31, 37, 40];
let gold = [16, 17, 24, 32, 38, 39];

let n = 0;// a counter
let cellw = cw / 7;// the width of a cell

//the loop:

  for (let y = cellw / 2; y < ch; y += cellw) {
    for (let x = cellw / 2; x < cw; x += cellw) {
    ctx.beginPath();
    ctx.arc(x, y, ar / 2, 0, 2 * Math.PI);
    //set the color of the circles
    for (let i = 0; i < red.length; i++) {
      if (n == red[i]) {
        ctx.fillStyle = "red";
        break;
      } else if (n == gold[i]) {
        ctx.fillStyle = "gold";
        break;
      } else {
        ctx.fillStyle = "white";
      }
    }
    ctx.fill();
    n++;
  }
}

body {
  background-color: #222;
  overflow: hidden;
}
canvas {
  background-color: #000;
  display: block;
  position:absolute;
  margin: auto;
  top:0;bottom:0;left:0;right:0
}

<canvas id="canvas"></canvas>

Rannie Aguilar Peralta · Accepted Answer · 2019-04-16 11:34:49Z

0

Yep, there's a problem in the for loop.

You just need to 2 loops for that.

for (let row = 0; row <= 6; row++) {
  for (let column = 0; column <= 6; column++) {
    circle(row * 30, column * 30, 20)
  } 
}

answered Apr 16, 2019 at 11:34

Rannie Aguilar Peralta

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