int temp=45; // variable for temperature
int redLED=10; // variable for LED
int greenLED=9;
int blueLED=8;

void setup() {
  // put your setup code here, to run once:
  pinMode(10, OUTPUT); // pin 10 configured as an output pin
  pinMode(9, OUTPUT);
  pinMode(8, OUTPUT);
}

void loop() {
  // if the temperature is larger then 35 on the LED:
  if(temp>35)
  {
    digitalWrite(redLED, HIGH);
    digitalWrite(greenLED, LOW);
    digitalWrite(blueLED, LOW);
      temp=33;
      delay(500);
  }
  else if (temp>30)
  {
    digitalWrite(redLED, LOW);
    digitalWrite(greenLED, HIGH);
    digitalWrite(blueLED, LOW);
      temp=22;
      delay(500);
  }
  else
  {
    digitalWrite(redLED, LOW);
    digitalWrite(greenLED, LOW);
    digitalWrite(blueLED, HIGH);
      temp=45;
      delay(500);
  }
}
/* the code "else if" is not working in the virtual environment. 
but if you give the else and then called the if after else and 
re-run the program it worked
Here the different temparature value are given in the loop but in reality it is 
measured by a thermometer*/