浮点数的比较

a>b   if( (a-b) > EPSINON)
a<b   if( (a-b) <-EPSINON)
a>=b if( (a-b) >= -EPSINON)
a<=b if( (a-b) <=  EPSINON)
a==b if ((a-b>=-EPSINON) && (a-b<=EPSINON))

 

 

#include
// Define your own tolerance

const double EPSILON = 1.00e-07;

const float   FLT_EPSILON  = 1.192092896e-07F;

const double  DBL_EPSILON  = 2.2204460492503131e-016;