Comparison problem

Can anyone tell me whats wrong with the code below.
In the stdio window, it shows whatever character I type with keyboard.
I want when I type ‘a’, the led at port a bit 1 is off, else the led is on.
But whatever character I type in, the led is always on.
What is the problem?

Thanks for helping.

void receive_data(char buf, int len)

* this is a user-function that will recieve the data
* as it comes in. (buf points to the buffer, len is the
* length of the data that was received.)
* Note - When this function returns, the buffer will be
* overwritten, so if you want the data, it should be
* coppied out of the buffer before the function returns.
* Nothing is done with it for now; it is just dropped on
* the floor.

 auto int i;