Crime Detecting Robot

/*

*/
const int trigpin = 9;
const int echopin = 10;
const int buzz = 5;
const int led = 7;

long duration;
int distance;

void setup() {
  pinMode(trigpin, OUTPUT);
  pinMode(echopin, INPUT);
  pinMode(buzz, OUTPUT);
  pinMode(led, OUTPUT);
  Serial.begin(9600); 
}

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("Distance: ");
   Serial.println(distance);
    
    if(distance <= 25){
  tone(buzz, 900);
  delay(200);
  noTone(buzz);
  delay(0);
} 

 if(distance <= 25){
  digitalWrite(led, HIGH);
  delay(50);
  digitalWrite(led, LOW);
  delay(50);
}
}