比较两个double或两个float值的最有效方法是什么?
简单地这样做是不正确的:
bool CompareDoubles1 (double A, double B)
{
return A == B;
}
Run Code Online (Sandbox Code Playgroud)
但是像这样:
bool CompareDoubles2 (double A, double B)
{
diff = A - B;
return (diff < EPSILON) && (-diff < EPSILON);
}
Run Code Online (Sandbox Code Playgroud)
似乎浪费处理.
有谁知道更聪明的浮动比较器?
我有以下代码进行双重比较.为什么我执行时变得不平等?
#include <iostream>
#include <cmath>
#include <limits>
bool AreDoubleSame(double dFirstVal, double dSecondVal)
{
return std::fabs(dFirstVal - dSecondVal) < std::numeric_limits<double>::epsilon();
}
int main()
{
double dFirstDouble = 11.304;
double dSecondDouble = 11.3043;
if(AreDoubleSame(dFirstDouble , dSecondDouble ) )
{
std::cout << "equal" << std::endl;
}
else
{
std::cout << "not equal" << std::endl;
}
}
Run Code Online (Sandbox Code Playgroud)