C++ Help with setf floatfield from string

*mit = 13311
std::istringstream iss(*mit);
double temp;
iss.setf(ios::fixed, ios::floatfield);
iss.precision(15);
iss >> temp;

std::cout<<"temp "<<temp<<endl; 
std::stringst开发者_高级运维ream ss;
ss<<temp / 1024;

I had tried with / without set precision, I still got 12.999, instead 12.9990234375 Please advise what did I do wrong? Thanks. Andrew

Add std::setprecision( 15 ) in the cout

 std::cout<< "temp " << std::setprecision( 15 ) << temp <<endl;

EDIT: sorry, if I got you wrong. You expect to see 12.9990234375 printed or you expect ss to be 12.9990234375 ? If the second, then make:

ss << std::setprecision(15) << temp / 1024;