求这两代码的区别，上面的代码不能画圆

var hourNumber=[3,4,5,6,7,8,9,10,11,12,1,2];

for(var i=0;i<hourNumber.length;i++){

var rad=2*Math.PI/12*i;

var y=Math.sin(rad)*(r-30);

var x=Math.cos(rad)*(r-30);

xtx.fillText(hourNumber[i],x,y);

}

/*hourNumber.forEach(function(number,i){

var rad =2*Math.PI/12*i;

var y=Math.sin(rad)*(r-30);

var x=Math.cos(rad)*(r-30);

xtx.fillText(number,x,y);

})*/