what coding language does unity use code example

Example 1: what language does unity use

C#: most used by far

Boo: obscure language that looks Python
UnityScript: version of JavaScript, but not identical to

Example 2: what does function setup() do in javascript

function setup() {
	create canvas(400, 400)
}

function draw(){
	if(mouseIsPressed){
		fill(0);
}else{
  fill(255)
}
  ellipse(mouseX, mouseY, 80, 80)
}

Example 3: What does @variable stand for in Ruby

@variable - is an "instance" variable. 
It can be accessed with any method inside the class.