reading data with serial communication between arduino and matlab problem

Hi

I want to read position of encoder which is coded in Arduino program with serial communication in Matlab

the code in arduino program is:

int counter = 0;
int aState;
int aLastState;

void setup() {
  pinMode (outputA, INPUT);
  pinMode (outputB, INPUT);
  Serial.begin(9600);
  aLastState = digitalRead(outputA);

}

void loop() {
aState = digitalRead(outputA);
if (aState != aLastState) {
  if (digitalRead(outputB) != aState) {
    counter ++;
  } else {
    counter --;
  }
  Serial.print("Position: ");
  Serial.println(counter);
}
aLastState = aState;
}
  }

and the code of Matlab is:

  s=serial('COM3');
fopen(s);
a=fscanf(s)

the problem is when the position is changed for example from 0 to 12 , when I use a=fscanf(s) it shows each values from 0 to 12 each times when I run this order I mean at the first time it shows 0 at the 2nd time it shows 1 at the3rd time it shows 2 etc.but I want to read the value of the position in real time how could I get this value?

[john white]

any help?