Check out example codes for "c# double question mark". It will help you in understanding the concepts better.
Code Example 1
int? a = null;
int b = a ?? -1; // Same as b = ( a != null ? a : -1 );
Console.WriteLine(b); // output: -1
//OR IF
int? a = 9;
int b = a ?? -1;
Console.WriteLine(b); // output: 9Learn ReactJs, React Native from akashmittal.com
