C++ 数据类型转换

wchar_t*,wchar_t,wchat_t数组,char,char*,char数组,std::string,std::wstring,CString....
#include <string>
// 使用CString必须使用MFC，并且不可包含<windows.h>
#define _AFXDLL
#include <afx.h>
using namespace std;
//----------------------------------------------------------------------------------
//将 单字节char* 转换为 宽字节 wchar*
inline wchar_t* AnsiToUnicode( const char* szStr )
{
int nLen = MultiByteToWideChar( CP_ACP, MB_PRECOMPOSED, szStr, -1, NULL, 0 );
if (nLen == 0)
{
return NULL;
}
wchar_t* pResult = new wchar_t[nLen];
MultiByteToWideChar( CP_ACP, MB_PRECOMPOSED, szStr, -1, pResult, nLen );
return pResult;
}
//----------------------------------------------------------------------------------
// 将 宽字节wchar_t* 转换 单字节char*
inline char* UnicodeToAnsi( const wchar_t* szStr )
{
int nLen = WideCharToMultiByte( CP_ACP, 0, szStr, -1, NULL, 0, NULL, NULL );
if (nLen == 0)
{
return NULL;
}
char* pResult = new char[nLen];
WideCharToMultiByte( CP_ACP, 0, szStr, -1, pResult, nLen, NULL, NULL );
return pResult;
}
//----------------------------------------------------------------------------------
// 将单字符 string 转换为宽字符 wstring
inline void Ascii2WideString( const std::string& szStr, std::wstring& wszStr )
{
int nLength = MultiByteToWideChar( CP_ACP, 0, szStr.c_str(), -1, NULL, NULL );
wszStr.resize(nLength);
LPWSTR lpwszStr = new wchar_t[nLength];
MultiByteToWideChar( CP_ACP, 0, szStr.c_str(), -1, lpwszStr, nLength );
wszStr = lpwszStr;
delete [] lpwszStr;
}
//----------------------------------------------------------------------------------
int _tmain(int argc, _TCHAR* argv[])
{
char*  pChar = "我喜欢char";
wchar_t* pWideChar = L"我讨厌wchar_t";
wchar_t  tagWideCharList[100] ;
char  ch = 'A';
char  tagChar[100] = {NULL};
CString  cStr;
std::string str;

// 注：设置语言环境以便输出WideChar
setlocale(LC_ALL,"chs");

// 注： char* 转换 wchar_t*
// 注： wchar_t 未重载 << ，所以不可使用 cout << 输出
pWideChar = AnsiToUnicode( pChar );
// 注：printf("%ls") 和 wprintf(L"%s") 一致
printf( "%ls\n", pWideChar );

// 注：wchar_t* 转换 wchar_t[]
wcscpy ( tagWideCharList, pWideChar );
wprintf( L"%s\n", tagWideCharList );

// 注：wchar_t[] 转换 wchar_t*
pWideChar = tagWideCharList;
wprintf( L"%s\n", pWideChar );

// 注：char 转换 string
str.insert( str.begin(), ch );
cout << str << endl;

// 注：wchar_t* 转换 string
pWideChar = new wchar_t[str.length()];
swprintf( pWideChar, L"%s", str.c_str());
wprintf( L"%s\n", pWideChar );

// 注：string 转换 char*
pChar = const_cast<char*>(str.c_str());
cout << pChar << endl;

// 注：char* 转换 string
str = std::string(pChar);
// 注： cout 的 << 重载了string, 若printf 的话必须 printf("%s", str.c_str());
//  而不可 print( "%s", str ); 因为 str 是个 string 类
cout << str << endl;

// 注：string 转换 char[]
str = "无聊啊无聊";
strcpy( tagChar, str.c_str() );
printf( "%s\n", tagChar );

// 注：string 转换 CString;
cStr = str.c_str();

// 注：CString 转换 string
str = string(cStr.GetBuffer(cStr.GetLength()));

// 注：char* 转换 CString
cStr = pChar;

// 注：CString 转换 char*
pChar = cStr.GetBuffer( cStr.GetLength() );

// 注：CString 转换 char[]
strncpy( tagChar, (LPCTSTR)CString, sizeof(tagChar));

// 注：CString 转换 wchar_t*
pWideChar = cStr.AllocSysString();
printf( "%ls\n", pWideChar );
}

____________________________________________________________________________________________

CString 转 wchar_t
CString path = "asdf";
wchar_t wstr[256] = path.AllocSysString();
或者：
wchar_t wcstring[256];
MultiByteToWideChar(CP_ACP,0,path,-1,wcstring,256);
wchar_t转CString
WideCharToMultiByte(CP_ACP,0,wcstring,256,
path.GetBuffer(0),256,NULL,NULL);
path.ReleaseBuffer(0);
string 转 CString
CString.format("%s", string.c_str());
char 转 CString
CString.format("%s", char*);
char 转 string
string s(char *);
string 转 char *
char *p = string.c_str();
CString 转 string
string s(CString.GetBuffer());
CString str = "fdjfdas";
string s = (LPCTSTR)str;
1，string -> CString
CString.format("%s", string.c_str());
用c_str()确实比data()要好.
2，char -> string
string s(char *);
你的只能初始化，在不是初始化的地方最好还是用assign().
3,CString -> string
string s(CString.GetBuffer());
GetBuffer()后一定要ReleaseBuffer(),否则就没有释放缓冲区所占的空间.