Problem handling for nullable types

 Public classCalc { Public Long? Number {Get;Set; }  Public LongNumber1 {Get;Set; }  Public LongNumber2 {Get;Set; } }varCalc =Newcalc (); Calc. Number1= -; Calc. Number2= -;varresult = Calc. Number + Calc. Number1+calc. Number2;

ReSharper also has no hint that the code has a problem, but the result of this code is wrong is null
Conclusion: Empty objects plus any number are empty objects
The right approach:
var result = Calc. Number.hasvalue? Calc. Number.value:0+ Calc. Number1+calc. Number2;
The result is 220.

Problem handling for nullable types