Programming in C++20

Course objectives

Delegates will learn:

• spaceship operator - implementation of comparisons in C++20
• new template features, such as concepts, template constraints, and the use of auto in template function declarations
• Ranges library - a new standard for collection processing in C++20
• new lambda expressions
• implementation of coroutines
• modularization of code – modules
• new API for multithreaded code

Course syllabus

Comparisons and <=> operator

• Safe comparisons for integral values
• Rewriting comparisons by compiler
• Defining operator == and operator <=> for structs & classes
• Using comparison categories with operator <=>
• Using operator <=> in generic code

Placeholder auto for function parameters

• Using auto as a placeholder for function parameters
• auto functions vs. generic lambdas

Constraints, requirements and concepts

• Constraints for templates
• requires clause
  • Ad hoc Boolean expressions
  • Using traits as constraints
  • Expression requires
• Concepts
  • Defining concepts
  • Using concepts
  • Subsuming concepts
  • Semantic constraints
• Standard concepts
  • Basic standard concepts
  • Concepts for iterators and ranges
  • Concept for callable objects
  • Auxiliary concepts

Ranges library in C++20

• Algorithms accepting ranges as input parameters
• Sentinels
• Projections
• Views
  • Generating Views
  • Filtering Views
  • Transforming Views
  • Mutating Views
• Utilities for ranges and views
• Borrowed iterators and ranges

New features in the core language

• Range-based loop with initialization
• Enumerations and using declaration
• Aggregates and designated initializers
• New attributes
• Feature test macros

New features in the standard library

• std::span
• Formatted output – std::format
• Dates and time zones
• New type traits
• Mathematical constants
• Bit operations in C++20

New features for lambda expressions

• Generic lambdas with template parameter
• Default constructors for lambdas
• Lambdas as Non-Type Template Parameters
• Consteval lambdas

Compile-time computations

• constinit
• consteval
• constexpr in C++20
• Writing constexpr functions using heap allocations (std::vector or std::string)

Coroutines

• Defining and using coroutine
• Coroutine frame, coroutine handle & promise type
• Using heap memory in coroutines
• Generators
• Awaitables and awaiters
• Coroutines and concurrency

Modules

• Implementing and exporting modules
• Compiling module units
• Importing and using modules
• Modules with multiple files
  • Module units
  • Internal partitions
  • Interface partitions

New concurrency features

• std::jthread and stop tokens
• Semaphores
• New features for atomic types
• Synchronized output streams

Prerequisites

Working knowledge of C++11/14/17

Course duration

3 days, 8 class hours each