Variadic functions are functions that can accept a variable number of arguments. In C++, this can be achieved using ellipsis (...) as the parameter. However, sometimes we may need to write multiple overloaded versions of a variadic function to handle different argument combinations.

To achieve this, we can use template specialization along with function overloading. We define a primary template function that handles the base case of the variadic function, and then specialize it for different argument combinations.

Here is an example of overloading a variadic function in C++:

#include <iostream>

// Primary template function
template <typename... Args>
void myFunction(Args... args) {
    std::cout << "Primary template called." << std::endl;
    // Process base case here
}

// Specialization for specific argument combination
template <>
void myFunction<int>(int arg) {
    std::cout << "Specialization for int called. Argument: " << arg << std::endl;
    // Process int case here
}

// Specialization for specific argument combination
template <>
void myFunction<double, int>(double arg1, int arg2) {
    std::cout << "Specialization for double and int called. Arguments: " << arg1 << ", " << arg2 << std::endl;
    // Process double and int case here
}

int main() {
    myFunction(1, 2.5); // Calls the primary template
    myFunction(10);     // Calls the specialization for int
    myFunction(3.14, 5); // Calls the specialization for double and int

    return 0;
}

In the above example, we define a primary template function myFunction that uses parameter pack Args to represent the variadic arguments. Inside the function body, we perform the base case processing.

Then, we provide two specializations of myFunction: one for int and another for double and int argument combinations. Inside each specialization, we perform the specific processing for the provided argument combination.

In the main function, we demonstrate how the overloaded variadic function can be called with different argument combinations. The appropriate specialization is called based on the provided arguments.

The output of the above program will be:

Primary template called.
Specialization for int called. Argument: 10
Specialization for double and int called. Arguments: 3.14, 5

By overloading variadic functions in C++, we can write code that handles different argument combinations efficiently, providing more flexibility and reusability in our programs.

#C++ #VariadicFunctions