From: eab AT salnet DOT org Date: Tue, 25 Mar 1997 19:20:10 -0500 Message-ID: Subject: Newbie troubles with Sin and Cos To: djgpp AT delorie DOT com > I'm trying to write a routine that spins a pixel around in a circle. > That works ok so far, except that the X and Y points are never next > to each other - I think I have narrowed it down to the results I am > getting from using COS and SIN. [snip] > result = sin(theta); > printf ("Sin of %i is %f\n",theta,result); [snip] > Am I using the wrong variable types to hold the results ? Do I need > to do something special in DJGPP to get the magic numbers ? This isn't specific to DJGPP, but applies to most programming languages--you need to convert the angle from degrees to radians, because that's what the trig functions take. In radians, pi equals 180 degrees, so to convert it to radians, you multiply it by 180/PI. This changes the line from your example to result = sin(theta*180/PI) (PI is a predefined value in math.h) > dberry AT dca DOT gov DOT au Ethan "The world beneath us spins in circles, And this life makes us twist and turn and sway, But we were made for more than rhythm with no reason By the One who moves with passion and with grace As He dances over all that He has made." --Steven Curtis Chapman This message sent via TRI-RIVERS INTERNET, Inc. - Salina, KS. !