Converting normal string/char to wide string/char and vice versa

When you are playing with wide charachters in C++, you sometimes need to covert it into normal charachters and vice versa. Here is a simple program that I picked up from somewhere but cant remember.

//Program tested on Microsoft Visual Studio 2008 - Zahid Ghadialy
//Program to convert from Wide to Narrow strings and Vice Versa
#include<iostream>
#include <sstream>

using namespace std;

wstring widen( const string& str)
{
  wostringstream wstm ;    
  const ctype<wchar_t>& ctfacet = use_facet< ctype<wchar_t> >( wstm.getloc() ) ;    
  for( size_t i=0 ; i<str.size() ; ++i )               
    wstm << ctfacet.widen( str[i] ) ;    
  return wstm.str() ;
} 

string narrow( const wstring& str )
{
  ostringstream stm ;    
  const ctype<char>& ctfacet = use_facet< ctype<char> >( stm.getloc() ) ;    
  for( size_t i=0 ; i<str.size() ; ++i )
    stm << ctfacet.narrow( str[i], 0 ) ;    
  return stm.str() ;}

int main()
{
  {      
    const wchar_t* wcstr = L"asdfg12345" ;    
    string cstr = narrow(wcstr);
    cout <<"\nOutput from wide to narrow = "<< cstr.c_str() << endl ;
  } 
  {
    const char* cstr = "zxcvb67890" ;    
    wstring wcstr = widen(cstr);
    wcout << L"\nOutput from narrow to wide = "<<wcstr.c_str() << endl ;
  }  
  return 0;
}

The output is as follows: