HELP ARDUINO CODE

Projects Programming
8 
// Adjust these constants to get the desired effect
const byte MIN_MOTOR_SPEED = 0;
const byte MAX_MOTOR_SPEED = 255;
const unsigned int MIN_DISTANCE_CM = 4;
const unsigned int MAX_DISTANCE_CM = 400;

void loop() {
    unsigned int distance_cm = getDistance_cm();

    // Check for target being out of range
    if (distance_cm == 0)
        distance_cm = MAX_DIESTANCE_CM;

   // Constrain the distance to the practical range of the sensor
   distance_cm = constrain(distance_cm, MIN_DISTANCE_CM, MAX_DISTANCE_CM);

    // Map the distance range to the speed range: close->slow, far->fast
    byte speed = map(distance_cm, MIN_DISTANCE_CM, MAX_DISTANCE_CM, MIN_MOTOR_SPEED, MAX_MOTOR_SPEED);

    // Set the motor speed
    motor1.setSpeed(speed); 
}