JuniorTheoryCommon

What does the program print (lines separated by spaces)?

string? name = null;
Console.WriteLine(name?.Length ?? -1);
name ??= "Anna";
name ??= "Bob";
Console.WriteLine(name);

-1 Anna

Expecting -1 Bob: ??= assigns only when the variable holds null, so the second line with ??= leaves "Anna" in place.
Expecting 0 or an exception: with null in name, name?.Length gives null without touching Length, and ?? turns it into -1.

JuniorTheoryCommon

string? name = null;
Console.WriteLine(name?.Length ?? -1);
name ??= "Anna";
name ??= "Bob";
Console.WriteLine(name);

-1 Anna

Expecting -1 Bob: ??= assigns only when the variable holds null, so the second line with ??= leaves "Anna" in place.
Expecting 0 or an exception: with null in name, name?.Length gives null without touching Length, and ?? turns it into -1.