What is the difference between template specialization and function overloading?

Template specialization and function overloading are both mechanisms in C++ that allow you to provide different implementations based on the types involved, but they serve different purposes and have some key differences.

Template Specialization

• Template specialization allows you to provide a specific implementation of a template for a particular set of template arguments.
• It is used when you want to customize the behavior of a template for certain types.
• Specialization is done by providing a specialized version of the template with the specific types specified.
• The specialized version is chosen by the compiler based on the exact match of the template arguments.

1#include <iostream>
2
3template <typename T>
4void print(T value) {
5  std::cout << "Generic: " << value << std::endl;
6}
7
8template <>
9void print<int>(int value) {
10  std::cout << "Specialized for int: " << value
11    << std::endl;
12}

Function Overloading

• Function overloading allows you to define multiple functions with the same name but different parameter types or numbers of parameters.
• It is used when you want to provide different implementations based on the types or number of arguments passed to the function.
• Overloaded functions are selected by the compiler based on the best match of the arguments during the function call.

1#include <iostream>
2
3void print(int value) {
4  std::cout << "int: " << value << std::endl;
5}
6
7void print(std::string value) {
8  std::cout << "string: " << value << std::endl;
9}

When to use each one:

• Use template specialization when you have a generic template but need to provide a specific implementation for certain types. Specialization allows you to customize the behavior of the template for those specific types.
• Use function overloading when you want to provide different implementations based on the types or number of arguments passed to a function. Overloading allows you to define multiple functions with the same name but different parameters.

In some cases, you can achieve similar results using either template specialization or function overloading. However, template specialization is specifically used for templates, while function overloading is used for regular functions.

Function overloading is generally more common and is used when you have different implementations based on the types of arguments, while template specialization is used when you need to specialize the behavior of a template for specific types.

It's important to note that function overloading is resolved at compile-time based on the static types of the arguments, while template specialization is resolved based on the exact match of the template arguments.