Chris Dedman-Rollet
~ Per Astra Ad Astra ~

C++ templates are a powerful feature of the C++ programming language that allows developers to write generic code that can work with any data type. This is similar to how a function can be written to accept arguments of any type, but with templates, the code is generated at compile-time rather than being interpreted at runtime.

A template is like a recipe that tells the computer how to make something. For example, if you wanted to make a bunch of different types of cookies, you could use the same recipe but change up the ingredients to make chocolate chip cookies, oatmeal raisin cookies, and so on. In C++, templates work the same way - you can use the same code for different data types, like using the same recipe to make cookies with different ingredients.

Here's a simple example of how you might use a C++ template:

// define a template function that takes one parameter of type T 
template <typename T>
void print(T value) 
{
    // print the value to the screen
    std::cout << value << std::endl;
}

// in main() or another function, call the template function 
// with a few different types
int main()
{
    print(5);       // prints 5
    print("hello"); // prints hello
    print(3.14159); // prints 3.14159
    return 0;
}
                        

In this example, the print() function is a template that can be used to print any type of value to the screen. When you call the function, you specify the type of value that you want to print by putting it in angle brackets after the word template, like this: template <typename T>. Then, when you call the function and pass it a value, the C++ compiler will generate a new version of the function that is specifically designed to work with the type of value that you passed in.

Aside from reducing the amount of code that needs to be written, another advantage of using templates is that they can improve the performance of C++ programs. Since the code is generated at compile-time, the generated code can be optimized by the compiler, which can lead to faster execution times.

There are many other uses for C++ templates, and they can be a very useful tool for any C++ programmer. Whether you're writing a simple utility function or a complex piece of software, templates can help you write code that is more reusable, efficient, and easy to maintain.

I hope that this information has been helpful in providing an understanding of what templates are and how to use them in C++.