Course Content
C++ Templates
C++ Templates
Variadic Templates
Variadic templates stand as a pinnacle of this flexibility, allowing you to define functions and classes that can accept a variable number of arguments. They empower C++ programmers to write concise and efficient code that adapts to diverse scenarios.
Syntax of Variadic Templates
Variadic templates leverage the power of template parameter packs. A template parameter pack allows you to accept an arbitrary number of template arguments. The syntax for declaring a template parameter pack involves using an ellipsis (...
) after the type or template parameter.
Example
template<typename... Args> void printArgs(Args... args) { // Print all arguments (std::cout << ... << args) << '\n'; }
In this example, Args
is a template parameter pack that can accept zero or more template arguments. Inside the function printArgs, the ellipsis (...
) expands the pack, allowing you to access each individual argument.
Using Variadic Templates
Variadic templates are incredibly versatile and can be used in a variety of contexts. Some common use cases include:
- Logging and Debugging: You can create logging functions that accept a variable number of arguments to simplify debug output.
- Recursive Algorithms: Variadic templates are frequently employed in recursive algorithms where the number of arguments may vary.
- Container Classes: You can design container classes, such as tuples or variant types, using variadic templates to store heterogeneous data.
- Wrapper Functions: Variadic templates are useful for creating wrapper functions that forward arguments to other functions with different signatures.
main
#include <iostream> // Base case for recursion void print() { std::cout << std::endl; } // Recursive variadic template function template<typename T, typename... Args> void print(T first, Args... args) { std::cout << first << ' '; print(args...); // Recursive call } int main() { print(1, 2.5, "Hello", 'c'); }
In this example, the print function takes a variable number of arguments and recursively prints them until there are no more arguments left.
Everything was clear?