Struct declaration and behavior in C Sharp (C#) - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is a struct in C#?

A struct is a value type that can hold data and related functionality. It is used to create small data structures that have value semantics.

intermediate

How do structs differ from classes in C#?

Structs are value types stored on the stack, while classes are reference types stored on the heap. Structs do not support inheritance but can implement interfaces.

intermediate

Can a struct have a parameterless constructor in C#?

No, structs cannot have explicit parameterless constructors. The compiler provides a default one that initializes all fields to their default values.

beginner

What happens when you assign one struct variable to another?

The entire data is copied. Each struct variable has its own copy of the data, so changes to one do not affect the other.

intermediate

Why might you choose a struct over a class?

Use a struct when you need a small, lightweight object with value semantics, such as points, colors, or complex numbers, to avoid heap allocation and improve performance.

Which of the following is true about structs in C#?

A Structs are reference types.

B Structs support inheritance from other structs.

C Structs can have explicit parameterless constructors.

D Structs are value types and stored on the stack.

Structs are value types stored on the stack. They do not support inheritance and cannot have explicit parameterless constructors.

What happens when you pass a struct to a method?

A A copy of the struct is passed.

B A reference to the struct is passed.

C The struct is converted to a class.

D The struct is passed as null.

Passing a struct to a method copies the entire struct, so the method works with its own copy.

Which keyword is used to declare a struct in C#?

A class

B struct

C record

D interface

The keyword 'struct' is used to declare a struct in C#.

Can a struct implement interfaces in C#?

A Only if the interface has no methods.

B No, structs cannot implement interfaces.

C Yes, structs can implement interfaces.

D Only if the struct is declared as partial.

Structs can implement interfaces to provide specific behaviors.

Which of these is a reason to use a struct instead of a class?

A You want to avoid heap allocation for small data.

B You want reference semantics.

C You need inheritance.

D You want to use polymorphism.

Structs avoid heap allocation and are good for small data with value semantics.

Explain how structs behave differently from classes in C# regarding memory and copying.

Think about where data is stored and what happens when you assign one variable to another.

Describe when and why you would choose to use a struct instead of a class in your C# program.

Consider the size and behavior of the data you want to represent.