int main()
{
float fa = 1.111;
if( fa > -0.000001 && fa < 0.000001) //小数点后五个0
{
std::cout << "equals 0" << endl;
}
else
{
std::cout << "is not 0" << endl;
}
return 0;
}
原文：http://www.cnblogs.com/tylerhuang/p/4926456.html