strtod not working

I want to convert string to double. I don't know. So I googling. I found this link:
http://www.gidforums.com/t-1131.html

It does not work.
here's my code:

Code:

---

#include <iostream>
      #include <cmath>
      using namespace std;
   
   
      int main() {
   
          string aa = "1234.333";
          double akbar = strtod(aa.c_str());
          cout << akbar << endl;
      }

---

But I got this error:
/usr/include/stdlib.h: In function `int main()':
/usr/include/stdlib.h:160: error: too few arguments to function `double
strtod(const char*, char**)'
tes.cpp:9: error: at this point in file

os : linux slackware 9.1
compiler: : g++ 3.3.3

What is additional argument????

Look at the following webpage, it may help.
http://www.thinkage.ca/english/gcos/...ib/strtod.html

Quote:

---

STRTOD - convert string to double precision number.
(ANSI Standard)
Usage:
#include <stdlib.h>
dx = strtod( s, p );

Where:
const char *s;
is the string to be converted into a double precision number. This string may consist of any number of blanks and/or tabs, possibly followed by a sign, followed by a string of digits that may contain a decimal point, then an "e" or "E" possibly followed by a sign, followed by an integer. It may also be in the hexadecimal format used by the "%a" format of "printf".
char **p;
points to a pointer that will be set to the character immediately following the double precision number in the string "s". For example, with
s = "1.23y";
dx = strtod(s,p);

a pointer to the character 'y' would be placed in "*p". If no floating point number can be formed from "s", "*p" points to the first character of "s". If "p" is the NULL pointer, this sort of action does not take place.
double dx;
is the double precision number obtained from "s". If no conversion could be performed (because the string didn't start with a valid number), 0.0 is returned. If there was an overflow, "strtod" sets "errno" to ERANGE and returns positive or negative HUGE_VAL (where HUGE_VAL is a large positive double value defined in <math.h>). It there was an underflow, "strtod" returns 0.0.
Description:
"strtod" converts the string "s" into a double precision number. Conversion stops with the first character that cannot be part of such a number.

---

Code:

---

#include <iostream.h>
#include <string>
#include <stdlib.h>
#include <cmath>
int main() {

  string aa = "1234.333";
  double akbar = strtod(aa.c_str(), NULL);
  cout << akbar << endl;
  return ( EXIT_SUCCESS );
}

---

Returns: 1234.33


DeadPoet

Better to use stringstreams. They may not be as concise, but I feel they're more flexible:

Code:

---

#include <iostream>
#include <string>
#include <sstream>

using namespace std;

double stod ( string& s )
{
  double d;
  istringstream conv ( s );

  conv>> d;

  return d;
}

int main() {

  string aa = "1234.333";
  double akbar = stod ( aa );
  cout<< akbar <<endl;
}

---

Thanx guys!!! I keep that in my mind when I need to convert string to double. By the way, I have used atof function in my current program and I am too lazy to change it.

Enjoy.