template function in class c++

In C++, a template function is a function that can operate on multiple data types. It allows us to write a single function definition that can be used with different types of data.

To create a template function in C++, follow these steps:

Start by defining the function prototype. Use the keyword template followed by the typename keyword or the keyword class, followed by the name of the type parameter. For example, to create a template function called print that takes a single parameter of type T, the prototype would look like this:

template<typename T>
void print(T value);

Implement the function definition. Since the function is a template, the definition should be placed in the header file, rather than in a separate implementation file. The function implementation can be written as if it was a regular function, without specifying the actual type of the parameter. For example:

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

Use the template function by providing the actual type(s) when calling it. The compiler will generate the necessary function(s) based on the provided type(s). For example:

print(10); // Calls print<int>(10)
print(3.14); // Calls print<double>(3.14)
print("Hello"); // Calls print<const char*>("Hello")

If needed, you can also specify multiple type parameters for a template function. Simply separate the type parameters with commas in the template definition. For example:

template<typename T, typename U>
void swap(T& a, U& b) {
    T temp = a;
    a = b;
    b = temp;
}

Note that template functions are only instantiated for the types they are actually used with. This means that if you don't use a specific instantiation of the template function, it won't be included in the compiled code, reducing the size of the resulting executable.

That's it! You now have a basic understanding of how to create and use template functions in C++. Let me know if you have any further questions.