C# Interview Question #84

What is the null-coalescing operator (??) in C#?

Advanced C# Language Features Mid-Level Intermediate

Quick Interview Answer

The null-coalescing operator returns its left operand when that value is not null; otherwise, it evaluates and returns the right operand.

The null-coalescing operator returns its left operand when that value is not null; otherwise, it evaluates and returns the right operand.

It is commonly used to provide fallback values. The ??= operator assigns a value only when the target is currently null.

These operators reduce repetitive null-checking code and are frequently used with nullable reference and value types.

string? name = null;

string displayName = name ?? "Guest";

List<string>? items = null;
items ??= new List<string>();