const int trig = 4;
const int echo = 5;

void setup() {

Serial.begin(9600);
pinMode(trig, OUTPUT);
pinMode(echo, INPUT);
long cm;
long dur;

}

void loop() {
long duration, inches, cm;
digitalWrite(trig, LOW);
delayMicroseconds(2);
digitalWrite(trig, HIGH);
delayMicroseconds(10);
digitalWrite(trig, LOW);
dur = pulseIn(echo, HIGH);
cm = dur *10 / 294 / 2;
Serial.print(cm);
Serial.print("cm");
Serial.println();
delay(100);
}