Arduino code to read out digital dial indicator with data output port

dial.ino

int i;
int sign;
long value;
float result;
int clockpin = 4;  
int datapin = 5;
int type = 0;
#define INCH 1
#define MM 0

unsigned long tempmicros;


void setup() {
  Serial.begin(115200);
  pinMode(clockpin, INPUT);
  pinMode(datapin, INPUT);
}

void loop() {  
  while (digitalRead(clockpin)==LOW) {} //if clock is HIGH wait until it turns to LOW
  tempmicros=micros();
  while (digitalRead(clockpin)==HIGH) {} //wait for the end of the LOW pulse
  if ((micros()-tempmicros)>500) { //if the LOW pulse was longer than 500 micros we are at the start of a new bit sequence
    decode(); //decode the bit sequence
  }
}

void decode() {
  sign=1;
  type=MM;

  value=0;
  long value2=0;
  for (i=0;i<24;i++) {
    while (digitalRead(clockpin)==HIGH) { } //wait until clock returns to HIGH- the first bit is not needed
    while (digitalRead(clockpin)==LOW) {} //wait until clock returns to LOW
    if (digitalRead(datapin)==HIGH) {
      if (i<20) {
        value|= 1<<i;
      } else {
        value2|= 1<<i;
      }
      if (i==20) {
        sign=-1;
      }
      if (i==23) {
        type=INCH;
      }
    }
  }

  result=value/100.00*sign;  
  if(type==INCH) {
    result/=20; //inches include "halves" (and the binary value is thus higher order)
    Serial.println(result,4); //print result with 4 decimals
    //Serial.println("\"");
  } else {
    Serial.println(result,2); //print result with 2 decimals
    //Serial.println("mm");
  }
  //delay(1000);
}