String in scientific notation C++ to double conversion
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19-09-2019 - |
Question
I've got a database filled up with doubles like the following one:
1.60000000000000000000000000000000000e+01
Does anybody know how to convert a number like that to a double in C++?
Is there a "standard" way to do this type of things? Or do I have to roll my own function?
Right now I'm doing sth like this:
#include <string>
#include <sstream>
int main() {
std::string s("1.60000000000000000000000000000000000e+01");
std::istringstream iss(s);
double d;
iss >> d;
d += 10.303030;
std::cout << d << std::endl;
}
Thanks!
Solution
Something like this? This would be the "C++" way of doing it...
#include <sstream>
using namespace std;
// ...
string s = "1.60000000000000000000000000000000000e+01";
istringstream os(s);
double d;
os >> d;
cout << d << endl;
Prints 16.
OTHER TIPS
You want the standard c function atof ([A]SCII to [F]loat, but it actually uses doubles rather than floats).
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