#define TRIG_PIN 2 
#define ECHO_PIN 3 
void setup() {
 Serial.begin(9600);
 pinMode(TRIG_PIN, OUTPUT); // put your setup code here, to run once:
pinMode(ECHO_PIN, INPUT);
}

void loop() {
 long duration,distance;
 digitalWrite(TRIG_PIN, LOW);
 delayMicroseconds(2); 
 digitalWrite(TRIG_PIN, HIGH);
 delayMicroseconds(10);
 digitalWrite(TRIG_PIN,LOW);
 duration=pulseIn(ECHO_PIN,HIGH);
 distance=duration*0.034/2;
 Serial.print("Distance:");
 Serial.print(distance);
 Serial.println("cm");
 delay(1000);// put your main code here, to run repeatedly:

}