Nullary constructor
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In computer programming, a nullary constructor is a constructor that takes no arguments.[1] Also known as a 0-argument constructor, no-argument constructor,[2] parameterless constructor or default constructor.[3]
Object-oriented constructors
[edit]In object-oriented programming, a constructor is code that is run when an object is created. Default constructors of objects are usually nullary.[4]
Java example
[edit]public class MyInteger { private int data; // Nullary constructor public MyInteger() { this(0); } // Non-nullary constructor public MyInteger(int value) { this.data = value; } int getData() { return data; } void setData(int value) { data = value; }}C++ example
[edit]class Integer {private: int data;public: // Default constructor with parameters // Leaving parameters unspecified defaults to the default value Integer(int value = 0): data{value} {} [[nodiscard]] int getData() const noexcept { return data; } void setData(int value) noexcept { data = value; }}Algebraic data types
[edit]In algebraic data types, a constructor is one of many tags that wrap data. If a constructor does not take any data arguments, it is nullary.
Haskell example
[edit]-- nullary type constructor with two nullary data constructorsdata Bool = False | True-- non-nullary type constructor with one non-nullary data constructordata Point a = Point a a-- non-nullary type constructor with...data Maybe a = Nothing -- ...nullary data constructor | Just a -- ...unary data constructorSee also
[edit]References
[edit]- ^ "Default Constructor in Java – Class Constructor Example". freeCodeCamp.org. 2022-01-13. Retrieved 2022-03-23.
- ^ "No-argument Constructor". chortle.ccsu.edu. Retrieved 2022-03-23.
- ^ "Default constructors - cppreference.com". en.cppreference.com. Retrieved 2023-04-12.
- ^ Ottinger, Joseph B.; Linwood, Jeff; Minter, Dave (2022), Ottinger, Joseph B.; Linwood, Jeff; Minter, Dave (eds.), "An Introduction to Hibernate 6", Beginning Hibernate 6: Java Persistence from Beginner to Pro, Berkeley, CA: Apress, pp. 1–25, doi:10.1007/978-1-4842-7337-1_1, ISBN 978-1-4842-7337-1, retrieved 2022-03-23
 | This computer science article is a stub. You can help Wikipedia by expanding it. |
In computer programming, a nullary constructor is a constructor that takes no arguments.[1] Also known as a 0-argument constructor, no-argument constructor,[2] parameterless constructor or default constructor.[3]
Object-oriented constructors
In object-oriented programming, a constructor is code that is run when an object is created. Default constructors of objects are usually nullary.[4]
Java example
public class MyInteger { private int data; // Nullary constructor public MyInteger() { this(0); } // Non-nullary constructor public MyInteger(int value) { this.data = value; } int getData() { return data; } void setData(int value) { data = value; }}C++ example
class Integer {private: int data;public: // Default constructor with parameters // Leaving parameters unspecified defaults to the default value Integer(int value = 0): data{value} {} [[nodiscard]] int getData() const noexcept { return data; } void setData(int value) noexcept { data = value; }}Algebraic data types
In algebraic data types, a constructor is one of many tags that wrap data. If a constructor does not take any data arguments, it is nullary.
Haskell example
-- nullary type constructor with two nullary data constructorsdata Bool = False | True-- non-nullary type constructor with one non-nullary data constructordata Point a = Point a a-- non-nullary type constructor with...data Maybe a = Nothing -- ...nullary data constructor | Just a -- ...unary data constructorSee also
References
- ^ "Default Constructor in Java – Class Constructor Example". freeCodeCamp.org. 2022-01-13. Retrieved 2022-03-23.
- ^ "No-argument Constructor". chortle.ccsu.edu. Retrieved 2022-03-23.
- ^ "Default constructors - cppreference.com". en.cppreference.com. Retrieved 2023-04-12.
- ^ Ottinger, Joseph B.; Linwood, Jeff; Minter, Dave (2022), Ottinger, Joseph B.; Linwood, Jeff; Minter, Dave (eds.), "An Introduction to Hibernate 6", Beginning Hibernate 6: Java Persistence from Beginner to Pro, Berkeley, CA: Apress, pp. 1–25, doi:10.1007/978-1-4842-7337-1_1, ISBN 978-1-4842-7337-1, retrieved 2022-03-23
 | This computer science article is a stub. You can help Wikipedia by expanding it. |