where should “include” be put in C++

Question

I\'m reading some c++ code and Notice that there are "#include" both in the header files and .cpp files . I guess if I move all the "#include" in the fi

Answer 1

You can avoid multiple definition errors if you use "include guards".

(begin myheader.h)
#ifndef _myheader_h_
#define _myheader_h_
struct blah {};
extern int whatsit;
#endif //_myheader_h_

Now if you #include "myheader.h" in other header files, it'll only get included once (due to _myheader_h_ being defined). I believe MSVC has a "#pragma once" with the equivalent functionality.