Question

I want to use printf to display hex numbers in the form 0x###, but if the number is 0, I want to omit the 0x part.

Answer 1

printf('%#x', number); 

Note that this does exactly what you want. If the value of number is 0, it prints 0, otherwise it prints in hex. Example:

int x = 0; int y = 548548;  printf('%#x %#x\n', x, y); 

Results in:

0 0x85ec4