_set_output_format
Customizes output formats used by formatted I/O functions.
unsigned int _set_output_format(
unsigned int format
);
Параметры
- [in] format
An value representing the format to use.
Return value
The previous output format.
Заметки
_set_output_format is used to configure the output of formatted I/O functions such as printf. At present, the only formatting convention that can be changed by this function is the number of digits displayed in exponents in the output of floating point numbers.
By default, the output of floating point numbers by functions such as printf, wprintf, and related functions in the Visual C++ Standard C library prints three digits for the exponent, even if three digits are not required to represent the value of the exponent. Zeroes are used to pad the value to three digits. _set_output_format allows you to change this behavior so that only two digits are printed in the exponent unless a third digit is required by the size of the exponent.
To enable two-digit exponents, call this function with the parameter _TWO_DIGIT_EXPONENT, as shown in the example. To disable two digit exponents, call this function with an argument of 0.
Требования
Routine |
Required header |
|---|---|
_set_output_format |
<stdio.h> |
For more compatibility information, see Compatibility in the Introduction.
Эквивалент в .NET Framework
Not applicable. To call the standard C function, use PInvoke. For more information, see Platform Invoke Examples.
Пример
// crt_set_output_format.c
#include <stdio.h>
void printvalues(double x, double y)
{
printf("%11.4e %11.4e\n", x, y);
printf("%11.4E %11.4E\n", x, y);
printf("%11.4g %11.4g\n", x, y);
printf("%11.4G %11.4G\n", x, y);
}
int main()
{
double x = 1.211E-5;
double y = 2.3056E-112;
unsigned int old_exponent_format;
// Use the default format
printvalues(x, y);
// Enable two-digit exponent format
old_exponent_format = _set_output_format(_TWO_DIGIT_EXPONENT);
printvalues(x, y);
// Disable two-digit exponent format
_set_output_format( old_exponent_format );
printvalues(x, y);
}
1.2110e-005 2.3056e-112
1.2110E-005 2.3056E-112
1.211e-005 2.306e-112
1.211E-005 2.306E-112
1.2110e-05 2.3056e-112
1.2110E-05 2.3056E-112
1.211e-05 2.306e-112
1.211E-05 2.306E-112
1.2110e-005 2.3056e-112
1.2110E-005 2.3056E-112
1.211e-005 2.306e-112
1.211E-005 2.306E-112