Demo

//create variable to store my number 10

var circleSize = 100; //integer type

var isCircle = false; //boolean type 1,0,true,false

var slider;

var checkbox;

​

function setup() {

  createCanvas(windowWidth, windowHeight);

  background(100);

  slider = createSlider(0, 255, 0);

  slider.position(10, 10);

  slider.style('width', '200px');

  checkbox = createCheckbox('isCircle', false);

  checkbox.changed(changeIsCircle);

}

​

function draw() {

  background(255);

  circleSize = slider.value();

  if (isCircle == true)

  {

    circle(20, 50, circleSize);

  }

  else 

  {

    rect(20,50, circleSize);

  }

}

​

function changeIsCircle() {

    isCircle = this.checked();

}

​

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