Invalid floating point data may appear in the actual calculation. The formatted output to the file is 1.79769e+308, and the output to the interface is a large string of data. Either way is not very convenient for reading and searching. Invalid floating point data encountered during development is worth judging.

Invalid value definition As follows: # define InvalidDouble * * (double) (” \ XFF \ XFF \ XFF \ XFF \ XFF \ XFF \ xef \ x7f ”) A double   Price; . (calculation steps are omitted) Price = GetPrice (); // get data

Floating-point is treated as follows **Invalid data determination method **(price = = InvalidDouble)? 0: price,