singleinheritance

Single inheritance is a form of inheritance in object-oriented programming in which a class derives from exactly one base class. In such hierarchies, each class has a single lineage, and method resolution follows a single path from the derived class up to the root. Subclasses inherit fields and methods from their parent, can override inherited methods, and can introduce new members. Constructors typically invoke the base class constructor to ensure proper initialization.

Compared with multiple inheritance, where a class can derive from more than one base class, single inheritance avoids ambiguity in method resolution and reduces complexity. It eliminates the diamond problem since there is only one chain of parent classes for any given class. However, single inheritance can limit code reuse, as functionality from multiple sources must be obtained through other mechanisms such as composition, interfaces, or mixins.

Languages that implement single inheritance for classes include Java, C#, Kotlin, Swift, and Objective-C. These languages generally allow a class to inherit from one superclass while supporting additional behavior through interfaces or protocols. Some languages permit multiple inheritance of behavior via mixins or traits, but many mainstream languages intentionally restrict class inheritance to one parent to maintain simplicity and predictability.

Design considerations often favor single inheritance combined with composition or interface-based programming to achieve flexible, reusable code while avoiding tight coupling. See also: multiple inheritance, interfaces, composition.