VC++ 基础知识
1.符号就不多说明了 :: 作用域分辨符;. 访问类成员 ;-> 指针用之。
2.琳琅满目的类型:
LPSTR 32-bit指针,指向一个字符串
LPCTSTR 32-bit指针,指向一个常数字符串,此字符串可移植到Unicode和DBCS(双字节字集),指向每字符16字节的const类型字符串的指针
LPTSTR 32-bit指针,指向一个字符串,此字符串可移植到Unicode和DBCS(双字节字集),指向每字符16字节的字符串的指针.
LPCSTR 32-bit指针,指向一个常数字符串,指向每字符8字节的const类型字符串的指针。
LPWSTR 以\0结束的Unicode字符串,即双字节
在Windows数据类型中有以下描述:
Windows Data Types
LPCSTR : Pointer to a constant null-terminated string of 8-bit Windows (ANSI) characters.
LPCTSTR : An LPCWSTR if UNICODE is defined, an LPCSTR otherwise.
LPCWSTR : Pointer to a constant null-terminated string of 16-bit Unicode characters.
LPTSTR : An LPWSTR if UNICODE is defined, an LPSTR otherwise.
LPSTR : Pointer to a null-terminated string of 8-bit Windows (ANSI) characters.
LPWSTR : Pointer to a null-terminated string of 16-bit Unicode characters.
CHAR 8bit ansi字符
WCHAR 16bit unicode字符
TCHAR 如果定义了UNICODE宏(#def UNICODE),TCHAR 等同于WCHAR ,如果没有定义unicode宏,
TCHAR 等同于CHAR
LPCSTR: 等价于 const char * 只读ANSI字符串指针
CString: MFC中对字符串的包装的类,可以是ANSI也可以是Uncode
char* ANSI字符串指针
char[] ANSI字符数组,可以当成指针字符串来使用
CHAR 等价于char,单个ANSI字符
L("Hello") 表示转换成宽字符,用以支持Unicode
3.类型转换:
Decimal Conversions
Decimal To Hex
// Use _itoa( ) function and set radix to 16. char hexstring[10]; int number = 30; itoa( number, hexstring, 16); // In hexstring is 1e.
Hex To Decimal
// You can use strtol function and you can specify base. char * hexstring= "ABCDEF"; char * p; int number = strtol(hexstring, &p,16); // A function that does this bool HexToDecimal (char* HexNumber, int& Number) { char* pStopString; Number = strtol (HexNumber, &pStopString, 16); return (bool)(Number != LONG_MAX); }
Decimal to time
char *DecToTime(float fTime, char *szTime) { int nHrs, nMin, nSec; fTime *= 3600; nHrs = (int)fTime / 3600; nMin = (int)(fTime - nHrs * 3600) / 60; nSec = (int)(fTime - nHrs * 3600 - nMin * 60); wsprintf(szTime, "%02d.%02d.%02d Hrs.Min.Sec.", nHrs, nMin, nSec); return szTime; }
String Conversions
String to Hex
sscanf(string, %04X, &your_word16); // where string = your string and // 04 = length of your string and X = hex
Hex to CString
CString Str; unsigned char Write_Buff[1]; Write_Buff[0] = 0x01; Str.Format("0x0%x",Write_Buff[0]);
COleVariant to CString
CString strTemp; COleVariant Var; Var = "FirstName"; strTemp = Var.bstrVal; AfxMessageBox(strTemp);
CString to char pointer
CString MyString = "ABCDEF"; char * szMyString = (char *) (LPCTSTR) MyString;
char *pBuffer = new char[1024]; CString strBuf = "Test"; pBuffer = strBuf.GetBuffer(sizeof(pBuffer));
char pointer to CString
char * mystring = "12345"; CString string = mystring;
Double to CString including the fractional part
CString strValue,strInt, strDecimal; int decimal,sign; double dValue = 4.125; strValue = _fcvt(dValue,6,&decimal,&sign); // Now decimal contains 1 because there is // only one digit before the . strInt = strValue.Left(decimal); // strInt contains 4 strDecimal = strValue.Mid(decimal); // strDecimal contains 125 CString strFinalVal; strFinalVal.Format("%s.%s",strInt,strDecimal); // strFinalVal contains 4.125
Double To CString
CString strValue; int decimal,sign; double dValue = 123456789101112; strValue = _ecvt(dValue,15,&decimal,&sign);
CString To Double
strValue = "121110987654321"; dValue = atof(strValue);
CString to LPCSTR
CString str1 = _T("My String"); int nLen = str1.GetLength(); LPCSTR lpszBuf = str1.GetBuffer(nLen); // here do something with lpszBuf........... str1.ReleaseBuffer();
CString to LPSTR
CString str = _T("My String"); int nLen = str.GetLength(); LPTSTR lpszBuf = str.GetBuffer(nLen); // here do something with lpszBuf........... str.ReleaseBuffer();
CString to WCHAR*
CString str = "A string here" ; LPWSTR lpszW = new WCHAR[255]; LPTSTR lpStr = str.GetBuffer( str.GetLength() ); int nLen = MultiByteToWideChar(CP_ACP, 0,lpStr, -1, NULL, NULL); MultiByteToWideChar(CP_ACP, 0, lpStr, -1, lpszW, nLen); AFunctionUsesWCHAR( lpszW ); delete[] lpszW;
LPTSTR to LPWSTR
int nLen = MultiByteToWideChar(CP_ACP, 0, lptStr, -1, NULL, NULL); MultiByteToWideChar(CP_ACP, 0, lptStr, -1, lpwStr, nLen);
string to BSTR
string ss = "Girish"; BSTR _bstr_home = A2BSTR(ss.c_str());
CString to BSTR
CString str = "whatever" ; BSTR resultsString = str.AllocSysString();
_bstr_t to CString
#include <ANSIAPI.H> #include <comdef.h> _bstr_t bsText("Hai Bayram"); CString strName; W2A(bsText, strName.GetBuffer(256), 256); strName.ReleaseBuffer(); AfxMessageBox(strName); char szFileName[256]; GetModuleFileName(NULL,szFileName,256); AfxMessageBox(szFileName);
Character arrays
Char array to integer
char MyArray[20]; int nValue; nValue = atoi(MyArray);
Char array to float
char MyArray[20]; float fValue; fValue = atof(MyArray);
Char Pointer to double
char *str = " -343.23 "; double dVal; dVal = atof( str );
Char Pointer to integer
char *str = " -343.23 "; int iVal; iVal = atoi( str );
Char Pointer to long
char *str = "99999"; long lVal; lVal = atol( str );
Char* to BSTR
char * p = "whatever"; _bstr_t bstr = p;
Float to WORD and Vice Versa
float fVar; WORD wVar; fVar = 247.346; wVar = (WORD)fVar; //Converting from float to WORD. //The value in wVar would be 247 wVar = 247; fVar = (float)fVar; //Converting from WORD to float. //The value in fVar would be 247.00