wchar 与 char 的互换

 #include <iostream>   
 #include <stdio.h>

#include <windows.h>

 using namespace std;
//#include <tchar.h>
char *w2c(char *pcstr,const wchar_t *pwstr, size_t len);
void c2w(wchar_t *pwstr,size_t len,const char *str);
int main(int argc, char* argv[])
{
wchar_t pwstr[] =L"我是中国人";
printf("===============");
wprintf(L"原始数据 pwstr:%s",pwstr);
wchar_t pwstr2[20];
    char *pcstr = (char *)malloc(sizeof(char)*(2 * wcslen(pwstr)+1));
    memset(pcstr , 0 , 2 * wcslen(pwstr)+1 );
    w2c(pcstr,pwstr,2 * wcslen(pwstr)+1) ;
	printf("wchar=>char result:%s\n",pcstr);
   c2w(pwstr2,20,pcstr);
   wprintf(L"%s",pwstr2);
    free(pcstr) ;
   return 0;
}

//将wchar_t* 转成char*的实现函数如下：

char *w2c(char *pcstr,const wchar_t *pwstr, size_t len)
{
int nlength=wcslen(pwstr);
//获取转换后的长度
int nbytes = WideCharToMultiByte( 0, // specify the code page used to perform the conversion
0,         // no special flags to handle unmapped characters
pwstr,     // wide character string to convert
nlength,   // the number of wide characters in that string
NULL,      // no output buffer given, we just want to know how long it needs to be
0,
NULL,      // no replacement character given
NULL );    // we don't want to know if a character didn't make it through the translation
// make sure the buffer is big enough for this, making it larger if necessary
if(nbytes>len)   nbytes=len;
// 通过以上得到的结果，转换unicode 字符为ascii 字符
WideCharToMultiByte( 0, // specify the code page used to perform the conversion
0,         // no special flags to handle unmapped characters
pwstr,   // wide character string to convert
nlength,   // the number of wide characters in that string
pcstr, // put the output ascii characters at the end of the buffer
nbytes,                           // there is at least this much space there
NULL,      // no replacement character given
NULL );
return pcstr ;
}
//将char* 转成wchar_t*的实现函数如下：
//这是把asii字符转换为unicode字符，和上面相同的原理
void c2w(wchar_t *pwstr,size_t len,const char *str)
{
if(str)
    {
      size_t nu = strlen(str);
      size_t n =(size_t)MultiByteToWideChar(CP_ACP,0,(const char *)str,(int)nu,NULL,0);
      if(n>=len)n=len-1;
      MultiByteToWideChar(CP_ACP,0,(const char *)str,(int)nu,pwstr,(int)n);
      pwstr[n]=0;
    }
}

//或者用此种方法更好一些：============我自已做的

//把ascii 字符转换为unicode字符

//wchar_t* Cphone_hq::ctow(wchar_t *pwstr, const char *str)
//{
//wchar_t* buffer;
//if(str)
//    {
//      size_t nu = strlen(str);
//      size_t n =(size_t)MultiByteToWideChar(CP_ACP,0,(const char *)str,int(nu),NULL,0);
//      buffer=0;
//      buffer = new wchar_t[n+1];
//      //if(n>=len) n=len-1;
//     ::MultiByteToWideChar(CP_ACP,0,(const char *)str,int(nu),buffer,int(n));    
//
//   }
//return buffer;
//delete buffer;
//}