cheat sheets.

  %@			id
  %d, %D, %i		long
  %u, %U		unsigned long
  %hi			short
  %hu			unsigned short
  %qi			long long
  %qu			unsigned long long
  %x, %X		unsigned long printed as hexadecimal
  %o, %O		unsigned long printed as octal
  %f, %e, %E, %g, %G	double
  %c			unsigned char as ASCII character
  %C			unichar as Unicode character
  %s			char * (a null-terminal C string of ASCII characters)
  %S			unichar * (a null-terminated C string of Unicode characters)
  %p			void * (an address printed in hexadecimal with a leading 0x)
  %%			a % character