Chapter 34: Features of Language Versions

C++11

C++11 introduced numerous features that have significantly enhanced the language. Some of the key features are:

1. Move Semantics

• Move constructors and move assignment operators allow resources to be moved rather than copied.

2. Lambda Expressions

• Lambda expressions provide a concise way to define anonymous function objects.

3. Smart Pointers

• std::unique_ptr, std::shared_ptr, and std::weak_ptr for better memory management.

4. Auto Keyword

• auto keyword for type inference.

5. Range-based for Loop

• Range-based for loop for easier iteration over collections.

6. nullptr

• nullptr keyword to represent null pointers.

7. constexpr

• constexpr for constant expressions.

8. Static_assert

• static_assert for compile-time assertions.

9. Threading

• Thread support library including std::thread, std::mutex, std::lock_guard, and std::unique_lock.

10. Other Features

• Rvalue references, variadic templates, initializer lists, std::array, std::unordered_map, and std::unordered_set.

C++14

C++14 introduced several improvements and refinements to C++11 features:

1. Generic Lambdas

• Generic lambdas allow lambdas to accept parameters of different types.

2. Return Type Deduction

• Return type deduction for normal functions using auto.

3. Variable Templates

• Variable templates for defining templates for variables.

4. Relaxed constexpr

• Relaxed constraints on constexpr functions, allowing more complex expressions.

5. Other Enhancements

• std::make_unique, binary literals, digit separators, and deprecated attribute.

C++17

C++17 introduced several new features and enhancements:

1. std::optional

• std::optional for optional values.

2. std::variant and std::any

• std::variant and std::any for type-safe unions and type-erased containers.

3. Structured Bindings

• Structured bindings for unpacking tuples and other types.

4. if constexpr

• if constexpr for compile-time conditions.

5. std::string_view

• std::string_view for non-owning views of strings.

6. Parallel Algorithms

• Parallel versions of standard algorithms.

7. Filesystem Library

• Filesystem library for file and directory operations.

8. Other Features

• Nested namespaces, std::byte, and std::scoped_lock.

C++20

C++20 introduced major new features and improvements:

1. Concepts

• Concepts for constraining template parameters.

2. Ranges

• Ranges library for working with sequences.

3. Coroutines

• Coroutines for asynchronous programming.

4. Modules

• Modules for better code organization and faster compilation.

5. Three-way Comparison

• Three-way comparison operator (<=>) for spaceship operator.

6. Calendar and Time Zone Library

• Calendar and time zone library for date and time operations.

7. Expanded constexpr

• Expanded constexpr capabilities.

8. Other Enhancements

• Improved constexpr lambdas, std::format, and std::span.

C++23

C++23 introduced further improvements and new features:

1. Pattern Matching

• Pattern matching for more expressive code.

2. Standard Library Improvements

• Enhanced standard library components.

3. More Powerful Lambdas

• Lambdas with more powerful capabilities.

4. Other Enhancements

• Refinements and optimizations to existing features.

C++26 (Upcoming)

C++26 is expected to introduce new features and enhancements. Some of the anticipated features are:

1. Enhanced Modules

• Further improvements to the modules feature.

2. Improved Coroutines

• Enhancements and optimizations to the coroutines feature.

3. Advanced Pattern Matching

• More powerful pattern matching capabilities.

4. Reflection

• Reflection capabilities for introspection.

5. Other Enhancements

• Additional improvements and optimizations to existing features.

Conclusion

The evolution of C++ from C++11 to C++26 has brought numerous features and improvements, making the language more powerful, expressive, and efficient. Each version has introduced new capabilities that enhance the way developers write and manage C++ code.