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# Data Conversions - by example.

##### Decimal To Hexa :-
Use _itoa( ) function and set radix to 16.

```
char hexstring[10];
int number = 30;
itoa( number, hexstring, 16);

In hexstring is 1e.
```
##### Hexa To Decimal :-
```a)You can use strtol function and you can specify base.

char * hexstring= "ABCDEF";
char * p;
int number = strtol(hexstring, &p,16);

b) Or you can use this too

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 to Hexa :-
```
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 :-
a)	CString MyString = "ABCDEF";
char * szMyString = (char *) (LPCTSTR) MyString;

b)	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
#include
_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);

PART THREE :- 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

```