var a = 1;

var b = a;

a=2;

println("\(a),\(b)");//2,1

struct cs{

var v:Int = 99;

}

var i = cs();

var j = i;

i.v = 98;

println("\(i.v),\(j.v)");//98,99

class ca{

var v:Int;

init(var a:ca){//拷贝构造实现传值

self.v = a.v;

}

init(){

v = 100;

}

}

var x = ca();

var y = x;

var z = ca(a: x);

x.v = 200;

println("\(x.v),\(y.v),\(z.v)");//200,200,100

//Int、struct是copy，class是引用