Correct format specifier to print pointer or address?

Question

Which format specifier should I be using to print the address of a variable? I am confused between the below lot.

%u - unsigned integer

%x

Answer 1

As an alternative to the other (very good) answers, you could cast to uintptr_t or intptr_t (from stdint.h/inttypes.h) and use the corresponding integer conversion specifiers. This would allow more flexibility in how the pointer is formatted, but strictly speaking an implementation is not required to provide these typedefs.