Flags with Repeats

<div style='background:silver;padding:5px'>
<canvas id='usr' width=--snippet-w-- height=--snippet-h--></canvas>
<canvas id='ans' width=--snippet-w-- height=--snippet-h-- style='display:none'></canvas>
</div>

--snippet-usr--
drawFlag(document.getElementById('usr').getContext('2d'));
(()=>{
  --snippet-ans--
  drawFlag(document.getElementById('ans').getContext('2d'));
})();
let [a,b] = ['usr','ans']
    .map(id=>document.getElementById(id))
    .map(elem=>elem.getContext('2d').getImageData(0,0,elem.width,elem.height))
let diff = a.data.map((v,i) => v===b.data[i]?1:0).reduce((acc,v)=>acc+v,0)*100/a.data.length;
let fb = document.createElement('div');
fb.innerText = `Score: ${diff.toFixed(1)}`;
document.body.appendChild(fb);
fetch(`/reportProgress.php?uid=--snippet-uid--&qid=--snippet-qid--&score=${diff}`);

We can repeat a statement or block of statements with a for loop. The classic for loop takes the following form:

for(let i = 0; i< 10; i++){
   console.log(i);
}

The body of the loop runs 10 times, control variable i takes every value 0,1,2..9 in turn. We can use the value of i inside the loop if required.

1) Bahrain

The flag of Bahrain has a five irregular pentagons on a red background.

Each pentagon can be represented by five points such as (0,0), (64,0) (100,15) (64,31) and (0,31).

Input

function drawFlag(ctx) { ctx.fillStyle = 'red'; ctx.fillRect(0,0,250,155); for(let i=0;i<5;i++){ ctx.beginPath(); ctx.moveTo(0,0); ctx.lineTo(64,0); ctx.lineTo(100,15); ctx.lineTo(64,31); ctx.lineTo(0,31); ctx.fill(); } } function star(ctx) { ctx.beginPath(); [ [ 0,-50],[11,-16],[48,-16],[18,6],[30,41], [ 0,18],[-30,41],[-18,6],[-48,-16],[-11,-16] ].forEach((xy) => ctx.lineTo(xy[0],xy[1])); ctx.fill(); }

​x

 

1

function drawFlag(ctx)

2

{

3

  ctx.fillStyle = 'red';

4

  ctx.fillRect(0,0,250,155);

5

  for(let i=0;i<5;i++){

6

    ctx.beginPath();

7

    ctx.moveTo(0,0);

8

    ctx.lineTo(64,0);

9

    ctx.lineTo(100,15);

10

    ctx.lineTo(64,31);

11

    ctx.lineTo(0,31);

12

    ctx.fill();

13

  }

14

}

15

​

16

function star(ctx)

17

{

18

  ctx.beginPath();

19

  [ [ 0,-50],[11,-16],[48,-16],[18,6],[30,41],

20

    [ 0,18],[-30,41],[-18,6],[-48,-16],[-11,-16]

21

  ].forEach((xy) => ctx.lineTo(xy[0],xy[1]));

22

  ctx.fill();

23

}

24

​

Go reset

Output

function drawFlag(ctx)
{
  ctx.fillStyle = 'red';
  ctx.fillRect(0,0,250,155);
  for(let i=0;i<5;i++){
    ctx.beginPath();
    ctx.moveTo(0,0);
    ctx.lineTo(64,0);
    ctx.lineTo(100,15);
    ctx.lineTo(64,31);
    ctx.lineTo(0,31);
    ctx.fill();
  }
}

function star(ctx)
{
  ctx.beginPath();
  [ [ 0,-50],[11,-16],[48,-16],[18,6],[30,41],
    [ 0,18],[-30,41],[-18,6],[-48,-16],[-11,-16]
  ].forEach((xy) => ctx.lineTo(xy[0],xy[1]));
  ctx.fill();
}

function drawFlag(ctx)
{
  ctx.fillStyle = 'red';
  ctx.fillRect(0,0,200,150);
  ctx.translate(100,75);
  ctx.fillStyle='yellow';
  star(ctx);
}

function star(ctx)
{
  ctx.beginPath();
  [ [ 0,-50],[11,-16],[48,-16],[18,6],[30,41],
    [ 0,18],[-30,41],[-18,6],[-48,-16],[-11,-16]
  ].forEach((xy) => ctx.lineTo(xy[0],xy[1]));
  ctx.fill();
}