How do I continuously serial print last string of data received on Uno?

this help is possible if you:

  • describe how many bytes are sended
    because you need to define an array of char that is big enough to hold all bytes

  • describe what microcontroller you are using
    to check if this microcontroller has enough RAM to store each byte

  • post your complete sketch as a code-section

There is an automatic function for doing this in the Arduino-IDE
just three steps

  1. press Ctrl-T for autoformatting your code
  2. do a rightclick with the mouse and choose "copy for forum"
  3. paste clipboard into write-window of a posting

best regards Stefan