Check out example codes for "c# 8 null coalescing assignment". It will help you in understanding the concepts better.
Code Example 1
// C# 8 null coalescing assignment operator: a ??= b; // the same as: a = a ?? b;
Code Example 2
//the null coalescing operator for c# is ?? int? x = null; int y = 9; return x ?? y; //Will return the value of x if x is not null else return y
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