Draw function diagram

Hello I have a function like (y(x)=sin(x)) that i convert it to post fix and then execute it.means that i coud get y for each x value now I have a simple question I want to draw diagram of function. how I should do this I dont work with gd and also i donot now how I should done this.but i think that i should get a range for x and get y for each x but i dont know how I shold draw diagram after this Thanks Excuse me for my bad english