How to print a full double precision by google glog

Question

I am try to print a double variable a like this.

double a;
//some statements for a
LOG(INFO) << a;

How can I print a using full precision?

Answer 1

You should try

#include <iomanip>      // std::setprecision

double a = 3.141592653589793238;
LOG(INFO) << std::fixed << std::setprecision( 15 ) << a;

If that doesn't work you can convert it to an std::string and use std::stringstream

#include <sstream>      // std::stringstream 
#include <iomanip>      // std::setprecision 

double a = 3.141592653589793238;
std::stringstream ss;
ss << std::fixed << std::setprecision( 15 ) << a;
LOG(INFO) << ss.str();

Alternatively, if you want full precision you can use one of the above with this answer.

The first method is more than likely to be the most efficient way to do it.