splitting ASCII string to variables

Hi PaulS
Thanks mate
sorry for making silly mistakes. i am a mechanical stream student and have little(only a weak) experience in programming.

and now this is the thing .....
I am using a arduIMU to read euler angles(in the format roll,pitch,yaw). I have conected the tx pin of the imu to the rx1 pin of arduino mega.
The arduIMU serial.prints the euler angles. I need to use the arduino mega to read the data from arduimu through rx1 pin and store the values into corresponding variables (as roll=xx,pitch=xx,yaw=xx)in arduino mega board.

how can i do this ??