My impression is that you will need to format to string
first, and then replace trailing zeros with spaces.
C++ precision - behaviour of setprecision
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27-06-2022 - |
Pregunta
As I understand it the setprecision function specifies the minimal precision but when I run the following code I get only 3 numbers after the decimal point:
int main()
{
double a = 123.4567890;
double b = 123.4000000;
std::cout << std::setprecision(5) << a << std::endl; // Udesireble
std::cout.setf(std::ios::fixed);
std::cout << std::setprecision(5) << a << std::endl; // Desireble
std::cout << std::setprecision(5) << b << std::endl; // Udesireble
std::cout.unsetf(std::ios::fixed);
std::cout << std::setprecision(5) << b << std::endl; // Desireble
return 0;
}
which prints:
123.46 // Udesireble
123.45679 // Desireble
123.40000 // Udesireble
123.4 // Desireble
Is there any way I can avoid checking the number of digits after the decimal point myself in order to know whether to set fixed ?
Solución
Otros consejos
For the streams, you can use two functions.
setfill(char_type c)
, which set the character to write, to match with the number of needed character (more information here)
There is the setw(int) function, which set the width of field of the value to display. (documentation here )
Using these functions, you may have a solution
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