templateclass

A class template, often referred to as a template class, is a programming construct that defines a family of classes parameterized by one or more template parameters. These parameters can be types, values, or other templates, enabling a single definition to be reused for multiple types and configurations without duplicating code.

In C++, a class template begins with a template header and is followed by a class declaration. For example: template<class T> class Box { public: T value; Box(); }; This defines a template Box<T> that can hold any type T. The template is instantiated by providing concrete arguments, such as Box<int> intBox; which creates a specific type for that instance.

Class templates support generic programming by allowing containers and adapters to operate on any element type while maintaining a single implementation. They are widely used to implement standard containers like stacks, queues, vectors, and maps, as well as user-defined data structures that must be type-agnostic.

Specialization and partial specialization are features of class templates. An explicit specialization provides a tailor-made version for a particular type, for example template<> class Box<char> { /* specialized members */ }; Partial specialization allows customization for a subset of types, such as template<class T> class Box<std::vector<T>> { /* specialized for vectors */ }. These mechanisms enable optimized or behaviorally distinct implementations for specific type patterns.

Other related aspects include non-type template parameters, which allow compile-time values (e.g., template<int N> class Array { int data[N]; }), and variadic templates, which accept a parameter pack of types. In C++, template code is typically defined in headers to be available during compilation for all instantiations.