C / C++ / MFC

class Obj
{
    //...
};

Obj& function(Obj& temp = Obj())
{
    return temp;
}

int main()
{
    Obj myObj;
    myObj = function();

    //...

    return 0;
}

Obj& function()
{
    Obj temp = Obj();
    return temp;
}

#ifndef TEST_MATRIX_HPP
#define TEST_MATRIX_HPP

#include <boost/numeric/ublas/matrix.hpp>
#include <boost/numeric/ublas/matrix_expression.hpp>
namespace ublas = boost::numeric::ublas; // shortcut name

namespace VecMat {
	typedef ublas::matrix<double> MatrixD; // matrix of doubles

	template<class MT>
	std::ostream & operator<< (std::ostream & os,
	                           const ublas::matrix_expression<MT> & M)
	{
		// Note: the matrix_expression<MT> has only one method "()", which
		// returns "& MT" or "const & MT" - a ref. to the included matrix object.
		typename MT::const_iterator1 it1;
		typename MT::const_iterator2 it2;
		for (it1 = M().begin1(); it1 != M().end1(); ++it1) {
			for (it2 = it1.begin(); it2 != it1.end(); ++it2) {
				os << *it2 << "\t";
			}
			os << std::endl;
		}
		return os;
	}
}; // namespace Math
#endif

#include "test_matrix.hpp"
using std::cout;
using std::endl;
using VecMat::MatrixD;
using VecMat::operator<<;

// ---------------------------------------------------------------------------
// would be in a header file
void test1 ();
namespace Main {
	void test2 ();
}
// ---------------------------------------------------------------------------

void test1 ()
{
	MatrixD X(10,3);
	VecMat::operator<<(cout << endl, X) << endl;
	cout << "X =" << endl << X << endl;
}

void Main::test2 ()
{
	MatrixD X(10,3);
	VecMat::operator<<(cout << endl, X) << endl;
	cout << "X =" << endl << X << endl;
}

#ifndef TEST_OTHER_HPP
#define TEST_OTHER_HPP
#include <ostream>
using std::ostream;

namespace Main {
	class Foo {
		int n;
	};

	ostream & operator<< (ostream & os, Foo const & foo);
}
#endif

test_oper.cpp||In function 'void Main::test2()':|
test_oper.cpp|29|error: no match for 'operator<<' in '((std::basic_ostream<char>*)std::operator<< [with _Traits = std::char_traits<char>](((std::basic_ostream<char>&)(& std::cout)), ((const char*)"X =")))->std::basic_ostream<_CharT, _Traits>::operator<< [with _CharT = char, _Traits = std::char_traits<char>, std::basic_ostream<_CharT, _Traits>::__ostream_type = std::basic_ostream<char>](std::endl [with _CharT = char, _Traits = std::char_traits<char>]) << X'|
lib\gcc\mingw32\4.5.2\include\c++\ostream|108|note: candidates are: std::basic_ostream<_CharT, _Traits>::__ostream_type& std::basic_ostream<_CharT, _Traits>::operator<<(std::basic_ostream<_CharT, _Traits>::__ostream_type& (*)(std::basic_ostream<_CharT, _Traits>::__ostream_type&)) [with _CharT = char, _Traits = std::char_traits<char>, std::basic_ostream<_CharT, _Traits>::__ostream_type = std::basic_ostream<char>]|
...
||=== Build finished: 19 errors, 0 warnings (0 minutes, 1 seconds) ===|

void CMainFrame::OnGroupview()
{
.
.
.
m_RecentAlarms.ShowWindow(SW_HIDE);
}

void CMainFrame::OnGroupview()
{
.
.
.m_RecentAlarms.ShowWindow(SW_SHOW);
}

CMDIChildWnd* pChild = ((CMainFrame*)AfxGetMainWnd())->MDIGetActive();

typedef struct tagCEICUSTOMDLGINFOA {
    DWORD cbSize;
    HWND hWnd;
    LPCSTR lpCaption;
    DWORD dwDialog;
    DWORD dwFlags;
} CEICUSTOMDLGINFOA, *LPCEICUSTOMDLGINFOA;

typedef ATL::CStringT< TCHAR, StrTraitMFC_DLL< TCHAR > > CString;

CString _str = TEXT("ABCD");
TCHAR* _tstr = _str;

CString _str = TEXT("ABCD");
TCHAR* _tstr = (TCHAR*)(LPCTSTR)_str;