cpp17.tar.gz

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++

## Template Instantiation 

Templates can be implicitly and explicitly instantiated. Implicit instantiation means automatically and explicit means manually.
### Implicit
```c++
std::vector<int> vec{};
bool isSmaller<double>(fir, sec);
bool isSmaller(fir, sec);
```
### Explicit
```c++
template class std::vector<int>;
template bool std::vector<double>::empty() const;
template bool isSmaller<double>(double, double); 
template bool isSmaller(double, double);
```
## Lazy Evaluation
When a class is instantiated, only the method declarations are available.
> The definition of a method is only instantiated when it is used.

It is not necessary that all methods of class templates are valid for the template arguments. You can only use the methods, which are valid for a given instantiation.

# Template Instantiation 

Templates can be implicitly and explicitly instantiated. Implicit instantiation means automatically and explicit means manually.
## Implicit
```c++
std::vector<int> vec{};
bool isSmaller<double>(fir, sec);
bool isSmaller(fir, sec);
```
## Explicit
```c++
template class std::vector<int>;
template bool std::vector<double>::empty() const;
template bool isSmaller<double>(double, double); 
template bool isSmaller(double, double);
```
# Lazy Evaluation
When a class is instantiated, only the method declarations are available.
> The definition of a method is only instantiated when it is used.

It is not necessary that all methods of class templates are valid for the template arguments. You can only use the methods, which are valid for a given instantiation.

In this lesson, we'll learn about template instantiation.

Introduction

Basics

Details

Techniques

Design

Future

Conclusion

Template Instantiation

Template Instantiation

Implicit

Explicit

Lazy Evaluation