Converting an int to an unsigned char for display on a Nokia 5110
The idea is that I would read a list of ints from a file ( I have
several files that I would iterate through) and convert that list to
the unsigned char array on each loop iteration.

The file could be a stream of bytes just as well as a stream of ints (or uints). If it were, no conversion would need to be done - just read a byte &amp; store it, read a byte &amp; store it, ....  If instead, it is a character representation of values, &quot;37, 150, 8, ...&quot;, again, read the characters of one value, convert them to int8_t or  uint8_t and store them in your byte array. Look up the atoi() or sscanf() functions to do the conversion.