Core Language & Types interview questions

24 real Core Language & Types questions from the C# bank, as asked in Indian campus drives and tech interviews. Every question has a verified answer and an AI-tutor explanation on placd — free to start.

1. What is Value type?

Junior
  1. A.a type whose instances hold their data directly and are copied wholesale on assignment, typically living on the stack or inline within a containing object
  2. B.a wrapper, written with a trailing question mark on a value type, that adds the ability to represent the absence of a value alongside HasValue and Value members
  3. C.the implicit conversion of a value-type instance into an object reference, allocating a heap wrapper and copying the data into it
  4. D.a type whose variables hold a reference to an object on the managed heap, so assignment copies the reference and multiple variables can alias the same instance
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2. Which term means: "a type whose instances hold their data directly and are copied wholesale on assignment, typically living on the stack or inline within a containing object"?

Junior
  1. A.Value type
  2. B.Unboxing
  3. C.Class
  4. D.Nullable value type
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3. Which statement is correct?

Junior
  1. A.Value type — a type whose instances hold their data directly and are copied wholesale on assignment, typically living on the stack or inline within a containing object
  2. B.Value type — a value type, declared with a dedicated keyword, that cannot inherit from another such type, gets copy-by-value semantics, and is well suited to small immutable data
  3. C.Value type — the implicit conversion of a value-type instance into an object reference, allocating a heap wrapper and copying the data into it
  4. D.Value type — a reference type allocated on the heap that supports inheritance, polymorphism, and identity-based aliasing between variables
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4. What is Reference type?

Junior
  1. A.the explicit conversion of a previously wrapped object reference back to its underlying value type, requiring an exact type match or it throws InvalidCastException
  2. B.a local declaration whose compile-time type is inferred by the compiler from its initializer, written with a contextual keyword instead of an explicit type name
  3. C.a type whose variables hold a reference to an object on the managed heap, so assignment copies the reference and multiple variables can alias the same instance
  4. D.a reference type allocated on the heap that supports inheritance, polymorphism, and identity-based aliasing between variables
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5. Which term means: "a type whose variables hold a reference to an object on the managed heap, so assignment copies the reference and multiple variables can alias the same instance"?

Junior
  1. A.Nullable value type
  2. B.Reference type
  3. C.Implicitly typed local variable
  4. D.Unboxing
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6. Which statement is correct?

Junior
  1. A.Reference type — a type whose instances hold their data directly and are copied wholesale on assignment, typically living on the stack or inline within a containing object
  2. B.Reference type — a value type, declared with a dedicated keyword, that cannot inherit from another such type, gets copy-by-value semantics, and is well suited to small immutable data
  3. C.Reference type — the explicit conversion of a previously wrapped object reference back to its underlying value type, requiring an exact type match or it throws InvalidCastException
  4. D.Reference type — a type whose variables hold a reference to an object on the managed heap, so assignment copies the reference and multiple variables can alias the same instance
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7. What is Struct?

Mid
  1. A.a wrapper, written with a trailing question mark on a value type, that adds the ability to represent the absence of a value alongside HasValue and Value members
  2. B.the implicit conversion of a value-type instance into an object reference, allocating a heap wrapper and copying the data into it
  3. C.a reference type allocated on the heap that supports inheritance, polymorphism, and identity-based aliasing between variables
  4. D.a value type, declared with a dedicated keyword, that cannot inherit from another such type, gets copy-by-value semantics, and is well suited to small immutable data
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8. Which term means: "a value type, declared with a dedicated keyword, that cannot inherit from another such type, gets copy-by-value semantics, and is well suited to small immutable data"?

Mid
  1. A.Reference type
  2. B.Unboxing
  3. C.Struct
  4. D.Nullable value type
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9. Which statement is correct?

Mid
  1. A.Struct — a type whose instances hold their data directly and are copied wholesale on assignment, typically living on the stack or inline within a containing object
  2. B.Struct — a value type, declared with a dedicated keyword, that cannot inherit from another such type, gets copy-by-value semantics, and is well suited to small immutable data
  3. C.Struct — a type whose variables hold a reference to an object on the managed heap, so assignment copies the reference and multiple variables can alias the same instance
  4. D.Struct — a wrapper, written with a trailing question mark on a value type, that adds the ability to represent the absence of a value alongside HasValue and Value members
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10. What is Class?

Junior
  1. A.a local declaration whose compile-time type is inferred by the compiler from its initializer, written with a contextual keyword instead of an explicit type name
  2. B.a reference type allocated on the heap that supports inheritance, polymorphism, and identity-based aliasing between variables
  3. C.a type whose variables hold a reference to an object on the managed heap, so assignment copies the reference and multiple variables can alias the same instance
  4. D.a type whose instances hold their data directly and are copied wholesale on assignment, typically living on the stack or inline within a containing object
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11. Which term means: "a reference type allocated on the heap that supports inheritance, polymorphism, and identity-based aliasing between variables"?

Junior
  1. A.Nullable value type
  2. B.Value type
  3. C.Implicitly typed local variable
  4. D.Class
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12. Which statement is correct?

Junior
  1. A.Class — a reference type allocated on the heap that supports inheritance, polymorphism, and identity-based aliasing between variables
  2. B.Class — the implicit conversion of a value-type instance into an object reference, allocating a heap wrapper and copying the data into it
  3. C.Class — the explicit conversion of a previously wrapped object reference back to its underlying value type, requiring an exact type match or it throws InvalidCastException
  4. D.Class — a value type, declared with a dedicated keyword, that cannot inherit from another such type, gets copy-by-value semantics, and is well suited to small immutable data
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13. What is Boxing?

Mid
  1. A.a wrapper, written with a trailing question mark on a value type, that adds the ability to represent the absence of a value alongside HasValue and Value members
  2. B.the explicit conversion of a previously wrapped object reference back to its underlying value type, requiring an exact type match or it throws InvalidCastException
  3. C.a type whose variables hold a reference to an object on the managed heap, so assignment copies the reference and multiple variables can alias the same instance
  4. D.the implicit conversion of a value-type instance into an object reference, allocating a heap wrapper and copying the data into it
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14. Which term means: "the implicit conversion of a value-type instance into an object reference, allocating a heap wrapper and copying the data into it"?

Mid
  1. A.Nullable value type
  2. B.Boxing
  3. C.Reference type
  4. D.Implicitly typed local variable
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15. Which statement is correct?

Mid
  1. A.Boxing — a value type, declared with a dedicated keyword, that cannot inherit from another such type, gets copy-by-value semantics, and is well suited to small immutable data
  2. B.Boxing — the implicit conversion of a value-type instance into an object reference, allocating a heap wrapper and copying the data into it
  3. C.Boxing — a reference type allocated on the heap that supports inheritance, polymorphism, and identity-based aliasing between variables
  4. D.Boxing — a wrapper, written with a trailing question mark on a value type, that adds the ability to represent the absence of a value alongside HasValue and Value members
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16. What is Unboxing?

Mid
  1. A.a reference type allocated on the heap that supports inheritance, polymorphism, and identity-based aliasing between variables
  2. B.a local declaration whose compile-time type is inferred by the compiler from its initializer, written with a contextual keyword instead of an explicit type name
  3. C.a type whose instances hold their data directly and are copied wholesale on assignment, typically living on the stack or inline within a containing object
  4. D.the explicit conversion of a previously wrapped object reference back to its underlying value type, requiring an exact type match or it throws InvalidCastException
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17. Which term means: "the explicit conversion of a previously wrapped object reference back to its underlying value type, requiring an exact type match or it throws InvalidCastException"?

Mid
  1. A.Class
  2. B.Reference type
  3. C.Unboxing
  4. D.Implicitly typed local variable
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18. Which statement is correct?

Mid
  1. A.Unboxing — a reference type allocated on the heap that supports inheritance, polymorphism, and identity-based aliasing between variables
  2. B.Unboxing — the explicit conversion of a previously wrapped object reference back to its underlying value type, requiring an exact type match or it throws InvalidCastException
  3. C.Unboxing — a type whose variables hold a reference to an object on the managed heap, so assignment copies the reference and multiple variables can alias the same instance
  4. D.Unboxing — a local declaration whose compile-time type is inferred by the compiler from its initializer, written with a contextual keyword instead of an explicit type name
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19. What is Nullable value type?

Mid
  1. A.a wrapper, written with a trailing question mark on a value type, that adds the ability to represent the absence of a value alongside HasValue and Value members
  2. B.a value type, declared with a dedicated keyword, that cannot inherit from another such type, gets copy-by-value semantics, and is well suited to small immutable data
  3. C.a reference type allocated on the heap that supports inheritance, polymorphism, and identity-based aliasing between variables
  4. D.the implicit conversion of a value-type instance into an object reference, allocating a heap wrapper and copying the data into it
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20. Which term means: "a wrapper, written with a trailing question mark on a value type, that adds the ability to represent the absence of a value alongside HasValue and Value members"?

Mid
  1. A.Struct
  2. B.Unboxing
  3. C.Reference type
  4. D.Nullable value type
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21. Which statement is correct?

Mid
  1. A.Nullable value type — the explicit conversion of a previously wrapped object reference back to its underlying value type, requiring an exact type match or it throws InvalidCastException
  2. B.Nullable value type — a type whose instances hold their data directly and are copied wholesale on assignment, typically living on the stack or inline within a containing object
  3. C.Nullable value type — a wrapper, written with a trailing question mark on a value type, that adds the ability to represent the absence of a value alongside HasValue and Value members
  4. D.Nullable value type — a reference type allocated on the heap that supports inheritance, polymorphism, and identity-based aliasing between variables
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22. What is Implicitly typed local variable?

Junior
  1. A.a reference type allocated on the heap that supports inheritance, polymorphism, and identity-based aliasing between variables
  2. B.a local declaration whose compile-time type is inferred by the compiler from its initializer, written with a contextual keyword instead of an explicit type name
  3. C.the explicit conversion of a previously wrapped object reference back to its underlying value type, requiring an exact type match or it throws InvalidCastException
  4. D.a wrapper, written with a trailing question mark on a value type, that adds the ability to represent the absence of a value alongside HasValue and Value members
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23. Which term means: "a local declaration whose compile-time type is inferred by the compiler from its initializer, written with a contextual keyword instead of an explicit type name"?

Junior
  1. A.Unboxing
  2. B.Implicitly typed local variable
  3. C.Value type
  4. D.Class
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24. Which statement is correct?

Junior
  1. A.Implicitly typed local variable — a local declaration whose compile-time type is inferred by the compiler from its initializer, written with a contextual keyword instead of an explicit type name
  2. B.Implicitly typed local variable — a value type, declared with a dedicated keyword, that cannot inherit from another such type, gets copy-by-value semantics, and is well suited to small immutable data
  3. C.Implicitly typed local variable — a type whose instances hold their data directly and are copied wholesale on assignment, typically living on the stack or inline within a containing object
  4. D.Implicitly typed local variable — the explicit conversion of a previously wrapped object reference back to its underlying value type, requiring an exact type match or it throws InvalidCastException
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