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

p is the conversion specifier to print pointers. Use this.

int a = 42;

printf("%p\n", (void *) &a);

Remember that omitting the cast is undefined behavior and that printing with p conversion specifier is done in an implementation-defined manner.