Difficulty: Medium
Correct Answer: 1, 3, 5
Explanation:
Introduction / Context:Structs in C# are value types with specific rules. Some class-like features are allowed, while others are restricted, especially regarding inheritance and constructors.
Given Data / Assumptions:
Concept / Approach:Structs cannot be inherited; therefore, a protected accessibility level (which relies on inheritance) is not meaningful and is disallowed. Historically, user-defined parameterless constructors in structs were not allowed; the runtime provides a default parameterless constructor that zero-initializes fields. Methods are allowed in structs. Private fields and public fields are also allowed.
Step-by-Step Solution:
1) True — protected is illegal in structs.2) False — private fields are permitted inside structs.3) True — defining a user zero-arg constructor in a struct is not allowed in traditional C# versions (the runtime supplies one).4) False — public fields are allowed; though properties are typically preferred.5) True — methods like Showdata() are allowed within structs.Verification / Alternative check:Attempting to compile the sample as-is results in errors for protected and the explicit parameterless constructor.
Why Other Options Are Wrong:
Common Pitfalls:Assuming class rules apply verbatim to structs; they do not due to lack of inheritance.
Final Answer:1, 3, 5
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