C++ Concepts: Improve Type Safety with C++ 20/

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Templates in C++

Templates in C++

Get a brief overview of templates in C++.

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What are templates?

Templates is a feature of the C++ programming language that allows functions and classes to deal with generic types. This allows a function or class to handle a wide range of data types without having to rebuild it.

Here is a simple function template to add two numbers of any type.

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#include <iostream>
template <typename T>
T add(T a, T b) {
    return a+b;
}
int main() {
    int a{42};
    int b{66};
    std::cout << add(a, b) << '\n';
    long double x{42.42L};
    long double y{66.6L};
    std::cout << add(x, y) << '\n';
}

If we look at C++ Insights we’ll see that code was generated for both int and long double overload.

Template specialization

When a separate and unique implementation is required for a given data type, template specialization is used.

When we build a function or class template, the compiler generates a duplicate of it every time a ...