max with a rotary encoder

#define encoder0PinA 2
#define encoder0PinB 4

volatile unsigned int encoder0Pos = 0;

void setup() {

pinMode(encoder0PinA, INPUT);
digitalWrite(encoder0PinA, HIGH); // turn on pullup resistor
pinMode(encoder0PinB, INPUT);
digitalWrite(encoder0PinB, HIGH); // turn on pullup resistor

attachInterrupt(0, doEncoder, CHANGE); // encoder pin on interrupt 0 - pin 2
Serial.begin (9600);
Serial.println("start"); // a personal quirk

}

void loop(){
// do some stuff here - the joy of interrupts is that they take care of themselves
}

void doEncoder(){
if (digitalRead(encoder0PinA) == HIGH) { // found a low-to-high on channel A
if (digitalRead(encoder0PinB) == LOW) { // check channel B to see which way
// encoder is turning
encoder0Pos = encoder0Pos - 1; // CCW
}
else {
encoder0Pos = encoder0Pos + 1; // CW
}
}
else // found a high-to-low on channel A
{
if (digitalRead(encoder0PinB) == LOW) { // check channel B to see which way
// encoder is turning
encoder0Pos = encoder0Pos + 1; // CW
}
else {
encoder0Pos = encoder0Pos - 1; // CCW
}

}
Serial.println (encoder0Pos, DEC); // debug - remember to comment out
// before final program run
// you don't want serial slowing down your program if not needed
}

thats the encoder code im using straight off the playground, but i dont understand where im getting these weird numbers, ive got 5v in the middle a resistor and then gnd in the left and right.