std::fixed,std::scientific,std::hexfloat,std::defaultfloat (3) Linux Manual Page
std::fixed,std::scientific,std::hexfloat,std::defaultfloat – std::fixed,std::scientific,std::hexfloat,std::defaultfloat
Synopsis
Defined in header <ios>
std::ios_base& fixed( std::ios_base& str ); (1)
std::ios_base& scientific( std::ios_base& str ); (2)
std::ios_base& hexfloat( std::ios_base& str ); (3) (since C++11)
std::ios_base& defaultfloat( std::ios_base& str ); (4) (since C++11)
Modifies the default formatting for floating-point input/output.
1) Sets the floatfield of the stream str to fixed as if by calling str.setf(std::ios_base::fixed, std::ios_base::floatfield)
2) Sets the floatfield of the stream str to scientific as if by calling str.setf(std::ios_base::scientific, std::ios_base::floatfield)
3) Sets the floatfield of the stream str to fixed and scientific simultaneously as if by calling str.setf(std::ios_base::fixed | std::ios_base::scientific, std::ios_base::floatfield). This enables hexadecimal floating-point formatting.
4) Sets the floatfield of the stream str to zero, as if by calling str.unsetf(std::ios_base::floatfield). This enables the default floating-point formatting, which is different from fixed and scientific.
This is an I/O manipulator, it may be called with an expression such as out << std::fixed for any out of type std::basic_ostream or with an expression such as in >> std::scientific for any in of type std::basic_istream.
Parameters
str – reference to I/O stream
Return value
str (reference to the stream after manipulation)
Notes
Hexadecimal floating-point formatting ignores the stream precision specification, as required by the specification of std::num_put::do_put.
Example
// Run this code
#include <iostream>
#include <sstream>
int main()
{
std::cout << "The number 0.01 in fixed: " << std::fixed << 0.01 << '\n'
<< "The number 0.01 in scientific: " << std::scientific << 0.01 << '\n'
<< "The number 0.01 in hexfloat: " << std::hexfloat << 0.01 << '\n'
<< "The number 0.01 in default: " << std::defaultfloat << 0.01 << '\n';
double f;
std::istringstream("0x1P-1022") >> std::hexfloat >> f;
std::cout << "Parsing 0x1P-1022 as hex gives " << f << '\n';
}
Output:
See also
setprecision (function)