c++ - What does :: mean after declaring an object? -

i trying hello world stuff after completing the standard c++ tutorial. first thing tried doing drawing directly on screen without window. found this , works.

#include "stdafx.h" #include <windows.h> #include <iostream> using namespace std;  int _tmain(int argc, _tchar* argv[]) {     hdc screendc = ::getdc(0);     ::rectangle(screendc, 200, 200, 300, 300);      int exit; cin >> exit;     return 0; } 

but in standard c++ tutorial cover this

hdc screendc = ::getdc(0); ::rectangle(screendc, 800, 200, 300, 300); 

what rectangle member of?

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if don't mind have other questions might simple. if not don't worry it.

• as rectangle has window move on it, disappears. there callback let me know can repaint?

• how change color of rectangle?

• where can go learn this? every tutorial have found has been sparse , have been out of date. can book if that's need do. have tried following (sometimes success , not):

• http://msdn.microsoft.com/en-us/library/vstudio/bb384843.aspx

• http://www.winprog.org/tutorial/

• http://msdn.microsoft.com/en-us/library/ms533895(v=vs.85).aspx

:: accesses global namespace. namespace resolution. can drop :: if like, cruff.