where do the brackets go?

this probably seems like a noob question, but i forgot where the brackets go lol and now i have errors and i cant remember, heres my script

var weapon = 0;

function Update () {
}

function OnGUI () {
	if (GUI.Button (Rect (10,10,160,100), "Machineguns")) {
		(var weapon == 1);
	}
	if (GUI.Button (Rect (10,170,330,100), "Flamethrower")) {
		(var weapon == 2);
	}
	if (GUI.Button (Rect (10,330,490,100), "Cannon")) {
		(var weapon == 3);
	}
}

remove "==" and write "=", you are not in an if condition. Brackets are correct.