#define trig 4
#define echo 5
#define red 7
#define yellow 8
#define green 9
#define buzz 10

int distance =0;
void output_led(int);




void setup() {
  Serial.begin(9600);
  pinMode(trig, OUTPUT);
  pinMode(echo, INPUT);
  pinMode(red, OUTPUT);
  pinMode(yellow, OUTPUT);
  pinMode(green, OUTPUT);
  pinMode(buzz, OUTPUT);

}

void loop() {
  // put your main code here, to run repeatedly:
  digitalWrite(trig, HIGH);
  delayMicroseconds(10);
  digitalWrite(trig, LOW);


  int duration = pulseIn(echo, HIGH);
   distance = int(duration/58);
  delay(1000);
  Serial.print('Distance in cm: ');
  Serial.println(distance);
 output_led(distance);

}
void output_led( int distance)
{

if (distance>100)
{
digitalWrite(green, HIGH);
digitalWrite(red, LOW);
digitalWrite(yellow, LOW);
delay(1000);
}
else if(distance>=30 && distance<= 100 )
{
digitalWrite(green, LOW);
digitalWrite(red, LOW);
digitalWrite(yellow, HIGH);
delay(1000);

}
else
{
digitalWrite(green, LOW);
digitalWrite(red, HIGH);
digitalWrite(yellow, LOW);
tone(buzz, 400);
delay(1000);
noTone(buzz);
delay(1000);


}

}