string object conversion to double

[hannes]

Hi,

Is there a way to convert a string object directly to a double instead of this:

string str = "3.14159265";
double pi = atof( str.c_str() );

Hannes

[hamsterman]

http://www.cplusplus.com/articles/numb_to_text/

[Galik]

How more direct can you get than one instruction?

[naivnomore]

Not sure what do you mean by "directly". But here is an alternate approach:

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

int main()
{
string sd = "3.14159265";
double d;
istringstream iss(sd);
iss >> d;
cout << setprecision(9) << d << endl;
}

[Albatross]

You can overload =. That'll be quite short after you declare and define the overloaded operator (which takes some space, mind you), although what you posted is one of the shortest if not the shortest way of converting a string to a double.

-Albatross