beagleBone Black and Arduino Uno UART Communication using c

I have wired BeagleBone Black. I read one benchmark test from BeagleBone Black GPIO Benchmark | Code and Life this link. and follow the result.
means use the c language to build bot using beaglebone black.
i need two communication:

  1. UART

  2. I2C
    in between two boards:

  3. Beaglebone black

  4. Arduino Uno