A proportional line follower written in ROBOTC for LEGO Mindstorms RCX

RCXSmoothFollow.c

#pragma config(Sensor, S1,     touch,               sensorTouch)
#pragma config(Sensor, S3,     light,               sensorReflection)
#pragma config(Motor,  motorA,          left,          tmotorNormal, openLoop, reversed)
#pragma config(Motor,  motorC,          right,         tmotorNormal, openLoop)
//*!!Code automatically generated by 'ROBOTC' configuration wizard               !!*//

task main()
{
  int darkVal;
  int lightVal;
  int avg;
  int error;
  int constant;
  int turn;
  int power;
  bool sensorTouched;
  sensorTouched = false;
  while (sensorTouched == false) // set dark value
  {
    if (SensorValue[touch] == 1)
    {
      darkVal = SensorValue[light];
      sensorTouched = true;
    }
  }

  SetUserDisplay(darkVal); // display dark value
  wait1Msec(1000);

  sensorTouched = false;
  while (sensorTouched == false) //set light value
  {
    if (SensorValue[touch] == 1)
    {
      lightVal = SensorValue[light];
      sensorTouched = true;
    }
  }

  SetUserDisplay(lightVal); // display light value

  avg = ((darkVal+lightVal)/2); // calculate average of dark and light values
  constant = 7; // define constant of proportionality; changing this value will change the robot's
                // responsiveness/sensitivity
  power = 75; // set base motor power

  while (true)
  {
    error = (SensorValue[light] - avg);
    turn = (constant*error);
    motor[left] = (power + turn);
    motor[right] = (power - turn);
  }
}