A cordial greeting to all.
I need help, I want a number for example 0.57, to be expressed as 0.5.
that is to say with only one decimal without rounding. I could express with a decimal but it is rounded, for example: 0.57, it is expressed in 0.6.
What code do I have to use?
You can control the rounding style of floating point numbers with:
FE_DOWNWARD : rounding down. FE_TONEAREST : rounding to the nearest representable number. FE_TOWARDZERO : Rounding to zero. FE_UPWARD : round up. In combination with the std::fesetround function, all belonging to the header <cfenv> . Since you need to round down, use that function like this:
auto f = 0.57f;
std::cout << f << '\n'; // Muestra 0.57
std::cout << std::setprecision(1) << f << '\n'; // Muestra 0.6
std::fesetround(FE_DOWNWARD); // Aplicamos el redondeo a la baja
std::cout << std::setprecision(2) << f << '\n'; // Muestra 0.56
std::cout << std::setprecision(1) << f << '\n'; // Muestra 0.5
In C ++ another solution can be
#include <iostream>
#include <iomanip>
#include<math.h>
using namespace std;
int main()
{
float num = 0.57;
cout<<floor(10*num)/10<< endl;
return 0;
}