C++ Brain Teasers: Exercise Your Mind/

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Discussion: A Specialized String Theory

Discussion: A Specialized String Theory

Execute the code to understand the output and gain insights into template specialization and overload resolution.

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Run the code

Now, it’s time to execute the code and observe the output.

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#include <iostream>
template<typename T>
void serialize(T&) { std::cout << "template\n"; } // 1
template<>
void serialize<>(const std::string&) { std::cout << "specialization\n"; } // 2
void serialize(const std::string&) { std::cout << "normal function\n"; } // 3
int main()
{
    std::string hello_world{"Hello, world!"};
    serialize(hello_world);
    serialize(std::string{"Good bye, world!"});
}

Understanding the output

Remember our serialization library from the String Theory puzzle? In the meantime, a C++ expert has come along and decided that everything is better with templates. Whether or not that’s true is another discussion, but it certainly makes overload resolution more interesting!

We find three definitions of serialize in the above code puzzle:

  • Line 4: This is the primary function template for serialize().

  • Line 7: This is an explicit specialization of this template for std::string. We can recognize it as a specialization by the empty template<> tag.

  • Line 9: Finally, we see a plain old non-template serialize function. ...

Function template and overload resolution