Producures in Arduino

procedure1()
{
  if (X[glow]==[/glow]Y)   // Note the double == is a compare, the single = is a assignment
  {
    Serial.println("X equals Y "); // or ...
  }
}

Check the codes in the tutorial section - http://arduino.cc/en/Tutorial/HomePage = Spending time there is not waited as you can learn an awfull lot about the coding of the Arduino.