Arduino/build/shared/examples/5.Control/switchCase/switchCase.pde

/*
  Switch statement
 
 Demonstrates the use of a switch statement.  The switch
 statement allows you to choose from among a set of discrete values
 of a variable.  It's like a series of if statements.
 
 To see this sketch in action, but the board and sensor in a well-lit
 room, open the serial monitor, and and move your hand gradually
 down over the sensor.
 
 The circuit:
 * photoresistor from analog in 0 to +5V
 * 10K resistor from analog in 0 to ground
 
 created 1 Jul 2009
 modified 4 Sep 2010
 by Tom Igoe 
 
 This example code is in the public domain.
 
 http://www.arduino.cc/en/Tutorial/SwitchCase
 */

// these constants won't change:
const int sensorMin = 0;      // sensor minimum, discovered through experiment
const int sensorMax = 600;    // sensor maximum, discovered through experiment

void setup() {
  // initialize serial communication:
  Serial.begin(9600);  
}

void loop() {
  // read the sensor:
  int sensorReading = analogRead(A0);
  // map the sensor range to a range of four options:
  int range = map(sensorReading, sensorMin, sensorMax, 0, 3);

  // do something different depending on the 
  // range value:
  switch (range) {
  case 0:    // your hand is on the sensor
    Serial.println("dark");
    break;
  case 1:    // your hand is close to the sensor
    Serial.println("dim");
    break;
  case 2:    // your hand is a few inches from the sensor
    Serial.println("medium");
    break;
  case 3:    // your hand is nowhere near the sensor
    Serial.println("bright");
    break;
  } 

}