asked on

Equivalent to Hex()

I'm looking for a C/C++ function to convert a number to a hex string. Much like VB's Hex() command. Does C++ have a built in function for this, or do I have to create my own?

thienpnguyen

#include <iostream>
#include <sstream>
#include <string>
using namespace std;

string toHex(long value)
{
ostringstream os;
os << hex << value;
return os.str();
}

thienpnguyen

If you want to use C function, you can use itoa or _itoa (depending your compiler)

http://msdn.microsoft.com/library/default.asp?url=/library/en-us/vccore98/html/_crt__itoa.2c_._i64toa.2c_._ui64toa.2c_._itow.2c_._i64tow.2c_._ui64tow.asp

char buffer[200];

itoa( Number, buffer, 16 );

ASKER CERTIFIED SOLUTION

enachemc

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Salte

char buffer[20];
int k = 20;

sprintf( buffer, "%08x", k);

buffer now hold the string "00000014" which is 20 in hex. The 0 in front means "use leading zeroes" and 8 means "minimum
8 characters wide".

Similar effect can be achieved with boost's formatter library which goes well together with ostream (ostringstream, cout,
ofstream etc).

Hope this is of help.

Alf

Gary Benade

some routines for c++ builder. Should help you if you decide to write your own

//---------------------------------------------------------------------------
String __fastcall TForm1::StrToBase16(char * Value, int Len)
{
char H[16] = {"0123456789ABCDEF"};
byte * pS;
char * pD;

String Result = "";
if( Value == NULL)
return Result;
if(Len < 0)
Len = strlen(Value);
Result.SetLength( Len * 2);
if( Len == 0)
return Result;
pD = (char*)Result.c_str();
pS = (char*)Value;
while( Len > 0)
{
*pD = H[ *pS >> 4];
pD++;
*pD = H[ *pS & 0X0F];
pD++;
pS++;
Len--;
}
return Result;
}
//---------------------------------------------------------------------------
String __fastcall TForm1::Base16ToStr(char * Value, int Len)
{
byte * pD;
byte V;
char * pS;
String Result = "";
if( Value == NULL)
return Result;
if(Len < 0)
Len = strlen(Value);
Result.SetLength((Len / 2) + 1);
pD = (char*)Result.c_str();
pS = (char*)Value;
while( Len > 0)
{
V = (Byte)UpCase(*pS);
pS++;
if( V > (Byte)'9')
*pD = V - (Byte)'A' + 10;
else
*pD = V - (Byte)'0';
V = (Byte)UpCase(*pS);
pS++;
*pD = *pD << 4;
if (V > (Byte)'9')
*pD = *pD | (V - (Byte)'A' + 10);
else
*pD = *pD | (V - (Byte)'0');
Len -= 2;
pD++;
}
Result.SetLength( (char*)pD - (char*)Result.c_str());
return Result;
}

Decimal

ASKER

I forgot to mention it needs to go into a CString, otherwise thienpnguyen's answers would also have worked equally well. Thanks people.

Much simpler than what I had come up with on my own (below) :)

/////////////////////////////////////

CString intToHex(int wInt) {

CString toRetString = "";

// divide into left and right halves, solve

int left=0;
int right=0;

if ((wInt & 1) == 1) right = right + 1;
if ((wInt & 2) == 2) right = right + 2;
if ((wInt & 4) == 4) right = right + 4;
if ((wInt & 8) == 8) right = right + 8;
if ((wInt & 16) == 16) left = left + 1;
if ((wInt & 32) == 32) left = left + 2;
if ((wInt & 64) == 64) left = left + 4;
if ((wInt & 128) == 128) left = left + 8;

      switch (right)
      {

      case 0: toRetString = "0"; break;
      case 1: toRetString = "1"; break;
      case 2: toRetString = "2"; break;
      case 3: toRetString = "3"; break;
      case 4: toRetString = "4"; break;
      case 5: toRetString = "5"; break;
      case 6: toRetString = "6"; break;
      case 7: toRetString = "7"; break;
      case 8: toRetString = "8"; break;
      case 9: toRetString = "9"; break;
      case 10: toRetString = "A"; break;
      case 11: toRetString = "B"; break;
      case 12: toRetString = "C"; break;
      case 13: toRetString = "D"; break;
      case 14: toRetString = "E"; break;
      case 15: toRetString = "F"; break;

      }

      switch (left)
      {

      case 0: toRetString = "0" + toRetString; break;
      case 1: toRetString = "1" + toRetString; break;
      case 2: toRetString = "2" + toRetString; break;
      case 3: toRetString = "3" + toRetString; break;
      case 4: toRetString = "4" + toRetString; break;
      case 5: toRetString = "5" + toRetString; break;
      case 6: toRetString = "6" + toRetString; break;
      case 7: toRetString = "7" + toRetString; break;
      case 8: toRetString = "8" + toRetString; break;
      case 9: toRetString = "9" + toRetString; break;
      case 10: toRetString = "A" + toRetString; break;
      case 11: toRetString = "B" + toRetString; break;
      case 12: toRetString = "C" + toRetString; break;
      case 13: toRetString = "D" + toRetString; break;
      case 14: toRetString = "E" + toRetString; break;
      case 15: toRetString = "F" + toRetString; break;

      }

      return toRetString;
}