Explore the power of C++ templates, from function and class basics to advanced features like instantiation and concepts, enhancing code flexibility, reusability, and abstraction without performance loss.

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C++17

C++20

Templates are one of the many powerful features of Modern C++ programming. And with each new C++ standard, they become more important. 

Templates provide an efficient way to make your code more flexible and reusable, this way you can avoid repeating code that would otherwise be identical except for different types. Templates also give you the ability to provide abstraction without a performance penalty.

However, templates can be difficult to apply, can be counterintuitive, and have tricky error messages.

This course gives you the necessary information to overcome these hurdles and dive into the advanced topics. You’ll visit the basics such as function and class templates, and then explore the details to templates such as instantiation and fold expressions. Our journey also includes techniques based on templates, the design, and future directions of templates such as concepts. Based on this exhaustive tour of templates, a basic understanding of C++ is sufficient to master this course.

Let’s get started!

Generic Programming Templates in C++

// foldExpression.cpp

#include <iostream>

template<typename... Args>
bool all(Args... args) { return (... && args); }

template<typename... Args>
bool any(Args... args) { return (... || args); }

template<typename... Args>
bool none(Args... args) { return not(... || args); }


int main(){
    
  std::cout << std::endl;

  std::cout << std::boolalpha;

  std::cout << "all(true): " << all(true) << std::endl;
  std::cout << "any(true): " << any(true) << std::endl;
  std::cout << "none(true): " << none(true) << std::endl;
  
  std::cout << std::endl;

  std::cout << "all(true, true, true, false): " << all(true, true, true, false) << std::endl;
  std::cout << "any(true, true, true, false): " << any(true, true, true, false) << std::endl;
  std::cout << "none(true, true, true, false): " << none(true, true, true, false) << std::endl;
  
  std::cout << std::endl;
  
  std::cout << "all(false, false, false, false): " << all(false, false, false, false) << std::endl;
  std::cout << "any(false, false, false, false): " << any(false, false, false, false) << std::endl;
  std::cout << "none(false, false, false, false): " << none(false, false, false, false) << std::endl;
  
  std::cout << std::endl;
}

## Explanation

In the above example, we have three predicates. 
* `all` function returns `true` only if all the values passed to it are `true`, else `false` because we're using `&&` as an operator.

* `any` function returns `true` if any passed value is `true`, else `false` because we're using `||` as an operator.

* `none` function returns `true` only if all the passed parameters are `false` because we're using `||` operator with `not` and it will invert the result.




In this lesson, we'll look at an examples of the fold expressions.

Introduction

Basics

Details

Techniques

Design

Future

Conclusion

- Examples