Function Templates

Template Specialization for Function Templates

How can my template function have different behaviour based on the template arguments?

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Template specialization allows you to provide a specific implementation of a function template for a particular type or set of template arguments. It is commonly used when you need to customize the behavior of a function template for certain types.

To specialize a function template, you define a specific version of the template for the desired type(s). The specialized version takes precedence over the generic template when the specified type(s) are used.

Here's an example:

// Generic function template
template <typename T>
void print(T value) {
  std::cout << "Generic: " << value << std::endl;
}

// Specialization for std::string
template <>
void print(std::string value) {
  std::cout << "Specialization: " << value << std::endl;
}

int main() {
  int intValue = 42;
  double doubleValue = 3.14;
  std::string stringValue = "Hello";

  // Calls the generic template
  print(intValue);
  
  // Calls the generic template
  print(doubleValue);
  
  // Calls the specialized version for std::string
  print(stringValue);
}

In this example, the print function template has a generic implementation that works for most types. However, a specialized version of print is defined for std::string, which provides a different implementation specific to strings.

When print is called with an int or double, the generic template is used. When print is called with an std::string, the specialized version is invoked instead.

Template specialization is useful in situations where:

  • You need to provide a different implementation for a specific type or set of types.
  • The generic template does not work correctly or efficiently for certain types.
  • You want to optimize the behavior of the function for specific types.

It's important to note that template specialization should be used judiciously and only when necessary, as it can increase code complexity and compile times if overused.

Answers to questions are automatically generated and may not have been reviewed.

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