Data Conversions

By VGirish | 28 Jun 2002

These are a few samples of data conversions which you can use for a quick reference

Introduction

Here are a few data conversions with small examples :-

Decimal Conversions

Decimal To Hex

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// 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

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// 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

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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

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sscanf(string, %04X, &your_word16);
// where string = your string and 

// 04 = length of your string and X = hex

Hex to CString

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CString Str;
unsigned char Write_Buff[1];
Write_Buff[0] = 0x01;
Str.Format("0x0%x",Write_Buff[0]);

COleVariant to CString

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CString strTemp;
COleVariant Var;
Var = "FirstName";
strTemp = Var.bstrVal;
AfxMessageBox(strTemp);

CString to char pointer

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CString MyString = "ABCDEF";
char * szMyString = (char *) (LPCTSTR) MyString;

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char *pBuffer = new char[1024];
CString strBuf = "Test";
pBuffer = strBuf.GetBuffer(sizeof(pBuffer));

char pointer to CString

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char * mystring = "12345";
CString string = mystring;

Double to CString including the fractional part

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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

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CString strValue;
int decimal,sign;

double dValue = 123456789101112;
strValue = _ecvt(dValue,15,&decimal,&sign);

CString To Double

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strValue = "121110987654321";
dValue = atof(strValue);

CString to LPCSTR

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CString str1 = _T("My String");
int nLen = str1.GetLength();
LPCSTR lpszBuf = str1.GetBuffer(nLen);
// here do something with lpszBuf...........

str1.ReleaseBuffer();

CString to LPSTR

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CString str = _T("My String");
int nLen = str.GetLength();
LPTSTR lpszBuf = str.GetBuffer(nLen);
// here do something with lpszBuf...........

str.ReleaseBuffer();

CString to WCHAR*

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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

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int nLen = MultiByteToWideChar(CP_ACP, 0, lptStr, -1, NULL, NULL);
MultiByteToWideChar(CP_ACP, 0, lptStr, -1, lpwStr, nLen);

string to BSTR

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string ss = "Girish";
BSTR _bstr_home = A2BSTR(ss.c_str());

CString to BSTR

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CString str = "whatever" ;
BSTR resultsString = str.AllocSysString();

_bstr_t to CString

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#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

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char MyArray[20];
int nValue;

nValue = atoi(MyArray);

Char array to float

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char MyArray[20];
float fValue;

fValue = atof(MyArray);

Char Pointer to double

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char *str = " -343.23 "; 
double dVal; 
dVal = atof( str );

Char Pointer to integer

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char *str = " -343.23 "; 
int iVal;
iVal = atoi( str );

Char Pointer to long

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char *str = "99999"; 
long lVal; 
lVal = atol( str );

Char* to BSTR

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char * p = "whatever";
_bstr_t bstr = p;

Float to WORD and Vice Versa

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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

Conclusion

All luck and have a great time. I've checked most of the code above, but if I've been wrong somewhere, I'd like to know about it so that I can modify it. Thank you.

License

This article has no explicit license attached to it but may contain usage terms in the article text or the download files themselves. If in doubt please contact the author via the discussion board below.

Taisung.Kim