In the formatting stage, we start with the high-level data values that we want to print out; for example, we might want to print the number of piano tuners in Chicago, which our program has computed as 225. Printing out the three-byte string "225" is easy; we've solved that in the preceding sections. The task of formatting is to get us from the number 225 (an int, let's say) to that three-byte string "225".
When printing numbers, we have many possible concerns: should the number be printed in base 10, base 16, base 8, base 2, or some other base? If the number is negative, presumably, we should prefix it with -; if it is positive, should we prefix it with +? Should we use thousands-separators, and if so, ...
