void setup() {
Serial.begin(9600);
// read the sensor:
int sensorReading = analogRead(A0);
// map the sensor range to a range of four options:
int i = map(sensorReading, sensorMin, sensorMax, 0, 5);
}
Reading the analog pin, and mapping the reading to some other range, are a waste of effort, since the variables that hold the data immediately go out of scope.
Why did you comment out the first case statement, but not it's ending break statement?
What does the switch statement have to do with arrays, and getting the wrong value from some (undefined) array?