"rb" because you don't want Windows to open the file in translated mode and munging its contents. Null-termination so that the same code can deal with both binary and text files. And I prefer all mallocs to follow the pattern malloc(sizeof(tp)*n) because it's less hassle than thinking about what types' sizes may vary. This rabbit hole is endless and we haven't even started covering my use of fseek/ftell/rewind!
