const int TrigPin=4;// #define Trigpin 4
const int EchoPin=2;// #define Echopin 2
long duration;
int distance;

void setup()
{
  Serial.begin(9600);
  pinMode(TrigPin, OUTPUT);
  pinMode(EchoPin, INPUT);
}

void loop()
{
  digitalWrite(TrigPin, LOW);
  delayMicroseconds(2);
  digitalWrite(TrigPin, HIGH);
  delayMicroseconds(10);
  digitalWrite(TrigPin, LOW);

  duration=pulseIn(EchoPin, HIGH);
  distance=duration*0.034/2;
  Serial.print("Dist:");
  Serial.print(distance);
  Serial.println(" cm");
}