// http://codingtra.in

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// Approximating Pi

// https://youtu.be/5cNnf_7e92Q

// https://thecodingtrain.com/CodingChallenges/095-approximating-pi.html

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const r = 200;

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let total = 0;

let circle = 0;

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let recordPI = 0;

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let resultP;

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function setup() {

  createCanvas(402, 402);

  resultP = createP("Approximated Value:");

  background(0);

  translate(width / 2, height / 2);

  stroke(255);

  strokeWeight(4);

  noFill();

  ellipse(0, 0, r * 2, r * 2);

  rectMode(CENTER);

  rect(0, 0, r * 2, r * 2);

}

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function draw() {

  translate(width / 2, height / 2);

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  for (let i = 0; i < 250; i++) {

    const x = random(-r, r);

    const y = random(-r, r);

    total++;

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    const d = x * x + y * y;

    if (d < r * r) {

      circle++;

      stroke(240, 99, 164);

    } else {

      stroke(45, 197, 244);

    }

    strokeWeight(1);

    point(x, y);

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    const pi = 4 * (circle / total);

    let recordDiff = Math.abs(Math.PI - recordPI);

    let diff = Math.abs(Math.PI - pi);

    if (diff < recordDiff) {

      recordDiff = diff;

      recordPI = pi;

      resultP.html(`Approximated Value: ${recordPI}`);

    }

  }

}

​