C / C++ / MFC

int nCP = 1252; // Example: Windows-1252
// Get required buffer size
int nSize = ::WideCharToMultiByte(nCP, 0, str.GetString(), -1, NULL, 0, NULL, NULL);
char *nstringw = new char[nSize];
::WideCharToMultiByte(nCP, 0, str.GetString(), -1, nstringw, nSize, NULL, NULL);

// Create a char/multi-byte string from wide string.
// Pass LPCSTR to constructor, so use casting or GetString()!
CStringA strA(str.GetString());
// Convert it back to a wide string
CStringW strW(strA.GetString());

• The code page passed to WideCharToMultiByte()
• The code page used by the CStringT class

// Default ANSI code page
int nCP = ::GetACP();
// Returns same as GetSystemDefaultLCID() when SetThreadLocale() has not been called.
LCID nLCID = ::GetThreadLocale();
TCHAR szACP[7];
if (::GetLocaleInfo(nLCID, LOCALE_IDEFAULTANSICODEPAGE, szACP, 7) != 0)
    nCP = _tstoi(szACP);

• The system locale including its default ANSI code page
• The user's locale including its default ANSI code page
• The thread's locale including its default ANSI code page
• The code page used by the CStringT class
• The code page passed to conversion functions in your code

node a(3); // a, will be deleted as a stack variable
a.next = new node(4); // b, will be deleted by unique_ptr of a
a.next->next = new node(5); // c, will be deleted by unique_ptr of b
// 1. deleting of b, not "tested" :) :
a.next = move(a.next->next); // is there a crash ?
// 2. then deleting of b, old style :) :
unique_ptr<node> temp = move(a.next->next);
a.next = move(temp);

struct node {
  int m_iData;
  node* m_pNext;

  node(int iData) : m_iData(iData), m_pNext(NULL) {}
  ~node() { delete m_pNext; }

  node* detach() { node* prevNext(m_pNext); m_pNext = NULL; return prevNext; }
} a(3);

They sought it with thimbles, they sought it with care;
They pursued it with forks and hope;
They threatened its life with a railway-share;
They charmed it with smiles and soap.

a.next = b;

thandy mitchell wrote:

can you please provide me with the algorithm on how to go about doing this work

1. Using Excel Automation (COM / OLE Dispatch) with the Excel type library. This requires an installed Excel on the machine running your application (which defines what Excel file versions can be read) and the Excel type library on the development machine.
2. Using ODBC or ADO (OLE DB). These are database interfaces that handle sheets from Excel files like databases tables. Drivers for XLS files are present on all Windows systems. Drivers for XLSX files are installed by Office 2007 or with the 'Microsoft Access Database Engine 2010 Redistributable' package.
3. Using a library. Examples are the ExcelFormat Library[^] here at CodeProject and the commercial LibXL[^] library.