Difference between

Question

I want to get a detailed explanation on the difference between using %d and %p type for printing pointer.

Also Why does

Answer 1

Those conversions are highly architecture dependent. One of the most clear distinctions are with the real mode 8086 where int is 16 bits and a (large model) pointer is 32 bits but has a segment and offset which are always written as segment:offset.

%d    takes 16 bits and displays it as a signed value  123
%p    takes a pointer and display it in address format    0fef:0004

Since %p was introduced relatively recently I don't know of any implementations but a PDP-11 library ought to implement it by display the 16-bit address in octal.