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Data Conversion Exammples
for C and C++.. |
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As you learn with C and C++ you can't simply 'cast' an integer to a string or a wchar to a char - you have to 'convert' the data.
In C/C++ you're working with the 'raw' data - bits and bytes - so to do any conversion - you have do it yourself or use one of the numerous libraries.
 | PART ONE: Decimal Conversions |  |
Decimal To Hexadecimal
Use_itoa() function and set radix to 16.
<?php
char hexstring[10];
int number = 30;
itoa(number, hexstring, 16);
In hexstring is1e .
Hexadecimal To Decimal
a) You can usestrtol function and specify base:
<?php
char *hexstring = "ABCDEF";
char *p;
int number = strtol(hexstring, &p, 16);
b) Or you can use this:
<?php
bool HexToDecimal(char* HexNumber, int& Number)
{
char* pStopString;
Number = strtol(HexNumber, &pStopString, 16);
return (bool)(Number != LONG_MAX);
}
Decimal to Time
<?php
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;
}
| PART TWO: String Conversions | |
String to Hexadecimal
<?php
sscanf(string, "%04X", &your_word16);
// where string = your string and 04 = length of your string and X = hex
Hex to CString
<?php
CString Str;
unsigned char Write_Buff[1];
Write_Buff[0] = 0x01;
Str.Format("0x0%x", Write_Buff[0]);
COleVariant to CString
<?php
CString strTemp;
COleVariant Var;
Var = "FirstName";
strTemp = Var.bstrVal;
AfxMessageBox(strTemp);
CString to Char Pointer
<?php
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
<?php
char *mystring = "12345";
CString string = mystring;
Double to CString including the fractional part
<?php
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
<?php
CString strValue;
int decimal, sign;
double dValue = 123456789101112;
strValue = _ecvt(dValue, 15, &decimal, &sign);
CString To Double
<?php
strValue = "121110987654321";
dValue = atof(strValue);
CString to LPCSTR
<?php
CString str1 = _T("My String");
int nLen = str1.GetLength();
LPCSTR lpszBuf = str1.GetBuffer(nLen);
// here do something with lpszBuf...........
str1.ReleaseBuffer();
CString to LPSTR
<?php
CString str = _T("My String");
int nLen = str.GetLength();
LPTSTR lpszBuf = str.GetBuffer(nLen);
// here do something with lpszBuf...........
str.ReleaseBuffer();
CString to WCHAR*
<?php
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
<?php
int nLen = MultiByteToWideChar(CP_ACP, 0, lptStr, -1, NULL, NULL);
MultiByteToWideChar(CP_ACP, 0, lptStr, -1, lpwStr, nLen);
string to BSTR
<?php
string ss = "Girish";
BSTR _bstr_home = A2BSTR(ss.c_str());
CString to BSTR
<?php
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);
| PART THREE: Character Arrays | |
Char array to integer
<?php
char MyArray[20];
int nValue;
nValue = atoi(MyArray);
Char array to float
<?php
char MyArray[20];
float fValue;
fValue = atof(MyArray);
Char Pointer to double
<?php
char *str = " -343.23 ";
double dVal;
dVal = atof(str);
Char Pointer to integer
<?php
char *str = " -343.23 ";
int iVal;
iVal = atoi(str);
Char Pointer to long
<?php
char *str = "99999";
long lVal;
lVal = atol(str);
Char* to BSTR
<?php
char *p = "whatever";
_bstr_t bstr = p;
Float to WORD and Vice Versa
<?php
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
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