Well.. such a conversion would only make sense if your WCHAR string only consisted of characters that can also be represented using CHAR. In that case, yiu can write a conversion function:

Code:
CHAR wide_to_narrow(WCHAR w)
{
    // simple typecast
    // works because UNICODE incorporates ASCII into itself
    return CHAR(w);
}
Now, you can perform the conversion using std::transform():

Code:
WCHAR[20] wstr = "blahblahandmoreblah";
CHAR[20] dest;
std::transform(wstr, wstr + 20, dest, wide_to_narrow);
Or, even better, use wstring and string instead of WCHAR and CHAR arrays:

Code:
std::wstring wstr = "blahblahandmoreblah";
std::string dest(wstr.length());
std::transform(wstr.begin(), wstr.end(), dest.begin(), wide_to_narrow);
Simple isn't it?