Book Image

Modern C++: Efficient and Scalable Application Development

By : Richard Grimes, Marius Bancila
Book Image

Modern C++: Efficient and Scalable Application Development

By: Richard Grimes, Marius Bancila

Overview of this book

C++ is one of the most widely used programming languages. It is fast, flexible, and used to solve many programming problems. This Learning Path gives you an in-depth and hands-on experience of working with C++, using the latest recipes and understanding most recent developments. You will explore C++ programming constructs by learning about language structures, functions, and classes, which will help you identify the execution flow through code. You will also understand the importance of the C++ standard library as well as memory allocation for writing better and faster programs. Modern C++: Efficient and Scalable Application Development deals with the challenges faced with advanced C++ programming. You will work through advanced topics such as multithreading, networking, concurrency, lambda expressions, and many more recipes. By the end of this Learning Path, you will have all the skills to become a master C++ programmer. This Learning Path includes content from the following Packt products: • Beginning C++ Programming by Richard Grimes • Modern C++ Programming Cookbook by Marius Bancila • The Modern C++ Challenge by Marius Bancila
Table of Contents (24 chapters)
Title Page
Copyright
About Packt
Contributors
Preface
12
Math Problems
13
Language Features
14
Strings and Regular Expressions
15
Streams and Filesystems
16
Date and Time
17
Algorithms and Data Structures
Index

Writing a recursive lambda


Lambdas are basically unnamed function objects, which means that it should be possible to call them recursively. Indeed, they can be called recursively; however, the mechanism for doing it is not obvious, as it requires assigning the lambda to a function wrapper and capturing the wrapper by reference. Though it can be argued that a recursive lambda does not really make sense and a function is probably a better design choice, in this recipe we will look at how to write a recursive lambda.

Getting ready

To demonstrate how to write a recursive lambda, we will consider the well-known example of the Fibonacci function. This is usually implemented recursively in C++, as follows:

    constexpr int fib(int const n) 
    { 
      return n <= 2 ? 1 : fib(n - 1) + fib(n - 2); 
    }

 

 

 

 

How to do it...

In order to write a recursive lambda function, you must perform the following:

  • Define the lambda in a function scope.
  • Assign the lambda to an std::function wrapper.
  • Capture the...