Serial Communication issue between arduino and PC

I have did that one way it is working but it is creating issue in two way communication

Krunalsidd:
I have did that one way it is working but it is creating issue in two way communication

Then post the test programs and a sample of their output.

...R

Krunalsidd:
I will increase size of msg to 16 from 4

17 if you want to receive a text message of 16 characters (see below comment).

I just see that you also have a problem here

     if (feedback_index < 4) // Make sure there is room
      {
        feedback_msg[feedback_index] = feedback; // Add char to array
        feedback_string += feedback_msg[feedback_index] ;
        feedback_index++;
        feedback_msg[feedback_index] = '\0'; // Add NULL to end
      }

If feedback_index equals 3, you store a byte, next increment feedback_index and write a '\0' outside the boundaries of your array.

Next question is why you have those msg and feedback_msg? They don't seem to serve a purpose as far as I can see. The below does the same as the above

     if (feedback_index < 4) // Make sure there is room
      {
        feedback_string += feedback;
        feedback_index++;
      }

Your code seems to be loosely based on code in Robin's Serial Input Basics; why don't you use that instead. That way you can also get rid of (part of) the Strings (capital S); those Strings will eventually bite you (they might already do)

You need one implementation for Serial and one inplementation for XBSerial.