if statement with multiple conditions

[fprete]

Friends:

In an if statement, if I want to indicate that any one of several inputs to the serial port should cause an event to occur, how is it coded? For instance, if I want a pin set high, or to serialPrint something if the serial port receives the character "a", the code might read as follows:

if (Serial.available() > 0);
{
char letter = Serial.read();
if (letter == 'a')
{
Serial.println (F("ON"));

However, what if I want the same thing done-- i.e., Serial.println (F("ON"))-- if the port receives an "a", or "b", or "c"?

I cannot seem to find an informative answer or tutorial.

Thank you in advance.

[Franklin97355]

http://arduino.cc/en/Reference/Boolean

[fprete]

Thank you very much.