How to Use Template Specialization

Syntax of Template Specialization

To understand how template specialization works, we first need to grasp what happens under the hood when a template is called with a specific data type.

When you call a template function with a particular type, the compiler generates a concrete instance of the template for that type. This process is called template instantiation. Essentially, the compiler substitutes the template parameter with the provided type and creates a specialized version of the function.

main

header

#include <iostream>

template<typename T>

T TemplateFunction(T value) { return value; }

int main()

{

// When the compiler encounters this line

// It generates a function for the specified type

// VVV

TemplateFunction<int>(5);

}


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#include <iostream>

template<typename T>
T TemplateFunction(T value) { return value; }

int main()
{
    // When the compiler encounters this line
    // It generates a function for the specified type
    //               VVV
    TemplateFunction<int>(5);
}

But first, it checks if a substitution for this function already exists. There's no point in generating multiple instances of this function if it's called with the same type repeatedly. With this knowledge, we can use it for our purposes.

Task

Swipe to start coding

Create a template specialization for the TemplateFunction that handles std::string data types.

Implement a specialization for TemplateFunction to process std::string parameters differently.
Ensure that any string passed as a parameter has "Specialized: " added to the beginning of the returned value.

Solution

solution

#include <iostream>

template<typename T>

T TemplateFunction(T value) { return value; }

template<>

std::string TemplateFunction(std::string value) { return "Specialized: " + value; }

int main()

{

std::cout << TemplateFunction<int>(5) << std::endl;

// The code below has to output "Specialized: five"

std::cout << TemplateFunction<std::string>("five") << std::endl;

}

Everything was clear?

Thanks for your feedback!

Section 4. Chapter 2

#include <iostream>

template<typename T>

T TemplateFunction(T value) { return value; }

// Write your code here

// ...

int main()

{

std::cout << TemplateFunction<int>(5) << std::endl;

// The code below has to output "Specialized: five"

std::cout << TemplateFunction<std::string>("five") << std::endl;

}

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