function
<ios> <iostream>
std::hexfloat
ios_base& hexfloat (ios_base& str);
Use hexadecimal floating-point format
Sets the floatfield format flag for the str stream to hexfloat.
When floatfield is set to hexfloat, floating-point values are written using hexadecimal format.
The floatfield format flag is both a selective and a toggle flag: it can take any of the following values, or none:
flag value | effect when set |
fixed | write floating-point values in fixed-point notation. |
scientific | write floating-point values in scientific notation. |
hexfloat | write floating-point values in hexadecimal format.
The value of this is the same as (fixed|scientific) |
defaultfloat | write floating-point values in default floating-point notation. This is the value by default (same as none, before any other floatfield bit is set). |
For standard streams, the floatfield format flag is set to defaultfloat on initialization.
Parameters
- str
- Stream object whose floatfield format flag is affected.
Because this function is a manipulator, it is designed to be used alone with no arguments in conjunction with the insertion (<<
) and extraction (>>
) operations on streams (see example below).
Return Value
Argument str.
Example
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20
|
// hexfloat floatfield
#include <iostream> // std::cout, std::hexfloat, std::defaultfloat
int main () {
double a = 3.1415926534;
double b = 2006.0;
double c = 1.0e-10;
std::cout.precision(5);
std::cout << "hexfloat:\n" << std::hexfloat;
std::cout << a << '\n' << b << '\n' << c << '\n';
std::cout << '\n';
std::cout << "defaultfloat:\n" << std::defaultfloat;
std::cout << a << '\n' << b << '\n' << c << '\n';
return 0;
}
| |
Possible output:
hexfloat:
0x1.921fb5p+1
0x1.f58000p+10
0x1.b7cdfep-34
defaultfloat:
3.14159
2006
1e-010
|
Data races
Modifies str. Concurrent access to the same stream object may cause data races.
Exception safety
Basic guarantee: if an exception is thrown, str is in a valid state.
See also
- fixed
- Use fixed floating-point notation (function
)
- scientific
- Use scientific floating-point notation (function
)
- defaultfloat
- Use default floating-point notation (function
)
- ios_base::flags
- Get/set format flags (public member function
)
- ios_base::setf
- Set specific format flags (public member function
)
- ios_base::unsetf
- Clear specific format flags (public member function
)