making decisions using input from the keyboard.

I am trying to write a program that will allow a user to make a choice of what to do, so if the user chooses to test the redLed and the button that chooses that program is pressed the arduino board will go to that program. My question is how do I allow communication with external input from the computer keyboard?

You have a program on the PC that sends serial data to the COM port that is the arduino.
Things like hyper terminal or such.
Or you can use applications written in any language. Processing is a popular language for this and is free.

Ok, so what I am trying to accomplish is this; if 1 is pressed then it goes to check redLed, if 2 is pressed it goes to check greenLed etc. How do I let the input from the user on the computer keyboard tell the arduino where to go? for example in the pbasic board you would use the debugin command, what is the command that the arduino uses?

Serial.read();

See:-

For input:-

For output:-
http://www.ladyada.net/learn/arduino/lesson4.html

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