


How can we write a generic function in C that accepts template functions as arguments?
Nov 01, 2024 pm 08:46 PMTemplate Function as a Template Argument: Defining Generic Functions with Template Template Parameters
The challenge of defining generic functions in C can be encountered when the internal functions are themselves generic. This article explores a solution using template template parameters to overcome this hurdle.
Consider the following code snippet illustrating the problem:
<code class="cpp">template<typename T> void a(T t) { // do something } template<typename T> void b(T t) { // something else } template< ...param... > // ??? void function() { param<SomeType>(someobj); param<AnotherType>(someotherobj); } void test() { function<a>(); function<b>(); }</code>
The difficulty arises in determining how to define the function template correctly. To resolve this, we employ a technique known as "template template parameters."
Template Template Parameters
Template template parameters enable us to pass template functions as arguments to other templates. This provides the flexibility to create generic functions that operate on a specific set of template functions.
However, there is a catch: we cannot directly pass template template functions as types. Instead, we must use a workaround with dummy structures.
Workaround Using Dummy Structures
The following code exemplifies the workaround:
<code class="cpp">template <typename T> struct a { static void foo (T = T ()) { } }; template <typename T> struct b { static void foo (T = T ()) { } }; struct SomeObj {}; struct SomeOtherObj {}; template <template <typename P> class T> void function () { T<SomeObj>::foo (); T<SomeOtherObj>::foo (); } int main () { function<a>(); function<b>(); }</code>
The dummy structures a and b serve as placeholders for the template functions. They provide a method foo that does nothing, primarily to satisfy the syntax requirements.
The function template accepts a template template parameter T, which specifies the type of template function to be executed. It then invokes foo for two different types of objects, SomeObj and SomeOtherObj.
By using this approach, we can define generic functions that operate on a set of template functions in a flexible and type-safe manner.
The above is the detailed content of How can we write a generic function in C that accepts template functions as arguments?. For more information, please follow other related articles on the PHP Chinese website!

Hot AI Tools

Undress AI Tool
Undress images for free

Undresser.AI Undress
AI-powered app for creating realistic nude photos

AI Clothes Remover
Online AI tool for removing clothes from photos.

Clothoff.io
AI clothes remover

Video Face Swap
Swap faces in any video effortlessly with our completely free AI face swap tool!

Hot Article

Hot Tools

Notepad++7.3.1
Easy-to-use and free code editor

SublimeText3 Chinese version
Chinese version, very easy to use

Zend Studio 13.0.1
Powerful PHP integrated development environment

Dreamweaver CS6
Visual web development tools

SublimeText3 Mac version
God-level code editing software (SublimeText3)

Hot Topics

Polymorphism in C is implemented through virtual functions and abstract classes, enhancing the reusability and flexibility of the code. 1) Virtual functions allow derived classes to override base class methods, 2) Abstract classes define interfaces, and force derived classes to implement certain methods. This mechanism makes the code more flexible and scalable, but attention should be paid to its possible increase in runtime overhead and code complexity.

Yes, function overloading is a polymorphic form in C, specifically compile-time polymorphism. 1. Function overload allows multiple functions with the same name but different parameter lists. 2. The compiler decides which function to call at compile time based on the provided parameters. 3. Unlike runtime polymorphism, function overloading has no extra overhead at runtime, and is simple to implement but less flexible.

The destructor in C is used to free the resources occupied by the object. 1) They are automatically called at the end of the object's life cycle, such as leaving scope or using delete. 2) Resource management, exception security and performance optimization should be considered during design. 3) Avoid throwing exceptions in the destructor and use RAII mode to ensure resource release. 4) Define a virtual destructor in the base class to ensure that the derived class objects are properly destroyed. 5) Performance optimization can be achieved through object pools or smart pointers. 6) Keep the destructor thread safe and concise, and focus on resource release.

C has two main polymorphic types: compile-time polymorphism and run-time polymorphism. 1. Compilation-time polymorphism is implemented through function overloading and templates, providing high efficiency but may lead to code bloating. 2. Runtime polymorphism is implemented through virtual functions and inheritance, providing flexibility but performance overhead.

Implementing polymorphism in C can be achieved through the following steps: 1) use inheritance and virtual functions, 2) define a base class containing virtual functions, 3) rewrite these virtual functions by derived classes, and 4) call these functions using base class pointers or references. Polymorphism allows different types of objects to be treated as objects of the same basis type, thereby improving code flexibility and maintainability.

Yes, polymorphisms in C are very useful. 1) It provides flexibility to allow easy addition of new types; 2) promotes code reuse and reduces duplication; 3) simplifies maintenance, making the code easier to expand and adapt to changes. Despite performance and memory management challenges, its advantages are particularly significant in complex systems.

C destructorscanleadtoseveralcommonerrors.Toavoidthem:1)Preventdoubledeletionbysettingpointerstonullptrorusingsmartpointers.2)Handleexceptionsindestructorsbycatchingandloggingthem.3)Usevirtualdestructorsinbaseclassesforproperpolymorphicdestruction.4

Polymorphisms in C are divided into runtime polymorphisms and compile-time polymorphisms. 1. Runtime polymorphism is implemented through virtual functions, allowing the correct method to be called dynamically at runtime. 2. Compilation-time polymorphism is implemented through function overloading and templates, providing higher performance and flexibility.
