Arduino IDE Coding

int trigPin = 9;
int echoPin = 10;

int button = 2;

int greenLed = 6;
int redLed = 7;

long duration;
int distance;

bool measuring = false;
int lastButtonState = HIGH;

void setup()
{
  pinMode(trigPin, OUTPUT);
  pinMode(echoPin, INPUT);

  pinMode(button, INPUT_PULLUP);

  pinMode(greenLed, OUTPUT);
  pinMode(redLed, OUTPUT);

  Serial.begin(9600);

  digitalWrite(greenLed, LOW);
  digitalWrite(redLed, HIGH);
}

void loop()
{
  int buttonState = digitalRead(button);

  if(buttonState == LOW && lastButtonState == HIGH)
  {
    measuring = !measuring;

    if(measuring == true)
    {
      Serial.println(“Measurement Started”);
      digitalWrite(greenLed, HIGH);
      digitalWrite(redLed, LOW);
    }
    else
    {
      Serial.println(“Measurement Stopped”);
      Serial.print(“Final Length = “);
      Serial.print(distance);
      Serial.println(” cm”);

      digitalWrite(greenLed, LOW);
      digitalWrite(redLed, HIGH);
    }

    delay(300);
  }

  lastButtonState = buttonState;

  if(measuring == true)
  {
    digitalWrite(trigPin, LOW);
    delayMicroseconds(2);

    digitalWrite(trigPin, HIGH);
    delayMicroseconds(10);
    digitalWrite(trigPin, LOW);

    duration = pulseIn(echoPin, HIGH);

    distance = duration * 0.034 / 2;

    Serial.print(“Length = “);
    Serial.print(distance);
    Serial.println(” cm”);

    delay(500);
  }
}