What is platform dependency of c plus plus?

Answer 1

C++ has no platform dependency. If a compiler exists for a platform (and few don't) code can be written for that platform. Where platforms have different methods to do the same thing, conditional compilation can be used to cater for those differences, thus the same source code can be compiled on any platform simply by changing the definitions used by the conditional compilation directives.

For instance, a program that caters for Unix and Windows platforms might contain the following conditional compilation:

#ifdef __unix__

#include <unistd.h>

#elif defined _WIN32

#include <windows.h>

#endif

The definition of __unix__ and _WIN32 must be mutually exclusive.