hex to decimal conversion !

[shrutilalwani]

hello !

how can i convert a hex to decimal in VC++?
any function available

[kedaman]

use atoi

[Shaunak]

Hi!!

There is no direct function(as far as i know) to convert a hex number to decimal, but it is very easy to write to simple function for that.

Regards
Shaunak

[CornedBee]

Conversion from hex to decimal... do you mean from hexadecimal representation to decimal representation or from hexadecimal representation to a real number?

Case b: use strtoi

Case a:

#include <string>
#include <sstream>
#include <iomanip>
using std::string;
using std::ostringstream;
using std::istringstream;
using std::hex;

void hextodecimal(const string &in, const string &out)
{
  int temp;
  istringstream iss(in);
  iss >> hex >> temp;
  ostringstream oss;
  oss << temp;
  out = oss.str();
}

should work.

[Jop]

Hi CB,
The code above tries to modify something that's const.

void hextodecimal(const string &in, const string &out)

so that should be

void hextodecimal(const string &in, string &out)

or if you want the function to return a value (which I think is more logical in this case)

string hextodecimal(const string &in)
{
  int temp;
  istringstream iss(in);
  iss >> hex >> temp;
  ostringstream oss;
  oss << temp;
  return oss.str();
}

[shrutilalwani]

thanks !
can we write hex to decimal conversion code in C ???

pls tell me... its sor of very urgent, my entire project is held up due to this

awaiting for a prompt reply

shruti !!!

[kedaman]

atoi what was i thinking its strtol as CB said, here's an example of how to use it:
http://www.cplusplus.com/ref/cstdlib/strtol.html

[transcendental]

Here's another alternate way.

#include<stdio.h>

void HexToDec(const char *HexStr, int *DecNum)
{
  sscanf(HexStr,"%x",DecNum);  
  return;
}

You can take it out of the function if you want.

[CornedBee]

Originally posted by Jop
Hi CB,
The code above tries to modify something that's const.

void hextodecimal(const string &in, const string &out)

so that should be

void hextodecimal(const string &in, string &out)

or if you want the function to return a value (which I think is more logical in this case)

string hextodecimal(const string &in)
{
  int temp;
  istringstream iss(in);
  iss >> hex >> temp;
  ostringstream oss;
  oss << temp;
  return oss.str();
}

Oops, right. But I don't want to return a string object, that involves too much memory copying IMO. So the non-const reference was what I wanted.