function setup() {

  createCanvas(400, 400);

}

​

/* in this user declared function we have

three parameters, parameterOne, parameterTwo and colour as

seen in line 11.

in lines 12 and 13 we call the function circle using those

parameters */

function iHaveParameters(parameterOne, parameterTwo, colour) {

  fill(colour);

  circle(parameterOne, parameterTwo, 200);

}

​

/* draw is a p5.js function */

function draw() {

  /* background and fill are p5.js functions */

  background('indigo');

  /* here we call the function iHaveParameters

  and pass two arguments, 200 and 200 to be used as 

  the parameters in the function */

  iHaveParameters(200, 200,'hotpink');

}

​

/* change the arguments in line 24 and observe the results */

/* create other function with parameters and call it 

in the draw function */