can you use both p5.js and processing code example

Example: is processing better than p5.js

i think it is. Though there are some major differences between them.

Processing - making a circle

void setup() {
	//difference here:
    size(600, 600);
    //in p5 this would be createCanvas
}

void draw() {
 background(//anything you want);
 //ellipse or circle
 circle(x, y, sizeX, sizeY);
}

p5.js - making a circle

function setup() {
	createCanvas(600, 600);
}

function draw() {
	background(//anything you want);
    //ellipse or circle
    ellipse(x, y, sizeX, sizeY);
}

these are just a few differences that I've noticed between the 2 editors
though they are both awesome. I would say that processing runs faster, 
but that might just be me.