Search icon CANCEL
Subscription
0
Cart icon
Your Cart (0 item)
Close icon
You have no products in your basket yet
Arrow left icon
Explore Products
Best Sellers
New Releases
Books
Videos
Audiobooks
Learning Hub
Free Learning
Arrow right icon
Learning C++ Functional Programming
Learning C++ Functional Programming

Learning C++ Functional Programming: Explore functional C++ with concepts like currying, metaprogramming and more

eBook
€8.99 €32.99
Paperback
€41.99
Subscription
Free Trial
Renews at €18.99p/m

What do you get with Print?

Product feature icon Instant access to your digital eBook copy whilst your Print order is Shipped
Product feature icon Paperback book shipped to your preferred address
Product feature icon Download this book in EPUB and PDF formats
Product feature icon Access this title in our online reader with advanced features
Product feature icon DRM FREE - Read whenever, wherever and however you want
OR
Modal Close icon
Payment Processing...
tick Completed

Shipping Address

Billing Address

Shipping Methods
Table of content icon View table of contents Preview book icon Preview Book

Learning C++ Functional Programming

Manipulating Functions in Functional Programming

In the previous chapter, we talked about modern C++ in depth, especially about the new feature in C++11--the Lambda expression. As we discussed earlier, the Lambda expression is useful in simplifying function notation. Thus, in this chapter, we will apply the power of the Lambda expression again, which will be used in functional code, especially when we talk about currying--the technique to split and reduce the current function.

In this chapter, we will discuss the following topics:

  • Applying the first-class function and higher-order function so that our functions can not only be invoked as a function, but also be assigned to any variable, pass a function, and return a function
  • Pure function, to avoid side effect in our function since it no longer contacts an outside state
  • Currying, as mentioned at the beginning of this chapter...

Applying the first-class function in all functions

The first-class function is just a normal class. We can treat the first-class function like any other data type. However, in the language that supports the first-class function, we can do the following tasks without invoking the compiler recursively:

  • Passing a function as another function's parameter
  • Assigning functions to variables
  • Storing functions in collections
  • Creating new functions from the existing functions at runtime

Fortunately, C++ can be used to solve the preceding tasks. We will discuss it in depth in the following topics.

Passing a function as another function's parameter

Let's start to pass a function as the function parameter. We will choose...

Getting acquainted with three functional techniques in the higher-order function

We discussed that in the first-class function, the C++ language treats the functions as the value, which means we can pass them to the other functions, assign to variables, and so on. However, we have another term in functional programming, that is, a higher-order function, which are functions that work on other functions. It means the higher-order function can pass functions as the argument and can also return a function.

The higher-order function concept can be applied to the function in general, like in a mathematical function, instead of the first-class function concept that can only be applied in the functional programming language. Now, let's examine the three most useful higher-order functions in functional programming--map, filter, and fold.

...

Avoiding the side effect with pure function

A pure function is a function that will always return the same result every time it is given the same input. The result doesn't depend on any information or state and won't produce a side effect, or a change of the system state outside of the function. Let's take a look at the following piece of code:

    /* pure_function_1.cpp */
#include <iostream>

using namespace std;

float circleArea(float r)
{
return 3.14 * r * r;
}

auto main() -> int
{
cout << "[pure_function_1.cpp]" << endl;

// Initializing a float variable
float f = 2.5f;

// Invoking the circleArea() function
// passing the f variable five times
for(int i = 1; i <= 5; ++i)
{
cout << "Invocation " << i << " -> ";
cout...

Reducing a multiple arguments function with currying

Currying is a technique to split a function that takes multiple arguments into evaluating a sequence of functions, each with a single argument. In other words, we create other functions based on a current function by reducing the current function. Let's suppose we have a function named areaOfRectangle(), which takes two parameters, length and width. The code will be like this:

    /* curry_1.cpp */

#include <functional>
#include <iostream>

using namespace std;

// Variadic template for currying
template<typename Func, typename... Args>
auto curry(Func func, Args... args)
{
return [=](auto... lastParam)
{
return func(args..., lastParam...);
};
}

int areaOfRectangle(int length, int width)
{
return length * width;
}

auto main() -> int
{
...

Summary

We have discussed that there are some techniques to manipulate a function. We will gain many advantages from it. Since we can implement the first-class function in the C++ language, we can pass a function as another function's parameter. We can treat a function as a data object so we can assign it to a variable and store it in the container. Also, we can compose a new function from the existing one. Moreover, by using map, filter, and fold, we can implement the higher-order function in every function we create.

Another technique we have to implement in gaining a better functional code is a pure function to avoid a side effect. We can refactor all the functions we have so it won't talk to outside variables or states and won't change and retrieve the value from the outside state. Also, to reduce the multiple arguments function so we can evaluate its sequence...

Left arrow icon Right arrow icon

Key benefits

  • Modularize your applications and make them highly reusable and testable
  • Get familiar with complex concepts such as metaprogramming, concurrency, and immutability
  • A highly practical guide to building functional code in C++ filled with lots of examples and real-world use cases

Description

Functional programming allows developers to divide programs into smaller, reusable components that ease the creation, testing, and maintenance of software as a whole. Combined with the power of C++, you can develop robust and scalable applications that fulfill modern day software requirements. This book will help you discover all the C++ 17 features that can be applied to build software in a functional way. The book is divided into three modules—the first introduces the fundamentals of functional programming and how it is supported by modern C++. The second module explains how to efficiently implement C++ features such as pure functions and immutable states to build robust applications. The last module describes how to achieve concurrency and apply design patterns to enhance your application’s performance. Here, you will also learn to optimize code using metaprogramming in a functional way. By the end of the book, you will be familiar with the functional approach of programming and will be able to use these techniques on a daily basis.

Who is this book for?

This book is for C++ developers comfortable with OOP who are interested in learning how to apply the functional paradigm to create robust and testable apps.

What you will learn

  • • Get to know the difference between imperative and functional approaches
  • • See the use of first-class functions and pure functions in a functional style
  • • Discover various techniques to apply immutable state to avoid side effects
  • • Design a recursive algorithm effectively
  • • Create faster programs using lazy evaluation
  • • Structure code using design patterns to make the design process easier
  • • Use concurrency techniques to develop responsive software
  • • Learn how to use the C++ Standard Template Library and metaprogramming in a functional way to improve code optimization
Estimated delivery fee Deliver to Czechia

Premium delivery 7 - 10 business days

€25.95
(Includes tracking information)

Product Details

Country selected
Publication date, Length, Edition, Language, ISBN-13
Publication date : Aug 10, 2017
Length: 304 pages
Edition : 1st
Language : English
ISBN-13 : 9781787281974
Vendor :
Microsoft
Category :
Languages :

What do you get with Print?

Product feature icon Instant access to your digital eBook copy whilst your Print order is Shipped
Product feature icon Paperback book shipped to your preferred address
Product feature icon Download this book in EPUB and PDF formats
Product feature icon Access this title in our online reader with advanced features
Product feature icon DRM FREE - Read whenever, wherever and however you want
OR
Modal Close icon
Payment Processing...
tick Completed

Shipping Address

Billing Address

Shipping Methods
Estimated delivery fee Deliver to Czechia

Premium delivery 7 - 10 business days

€25.95
(Includes tracking information)

Product Details

Publication date : Aug 10, 2017
Length: 304 pages
Edition : 1st
Language : English
ISBN-13 : 9781787281974
Vendor :
Microsoft
Category :
Languages :

Packt Subscriptions

See our plans and pricing
Modal Close icon
€18.99 billed monthly
Feature tick icon Unlimited access to Packt's library of 7,000+ practical books and videos
Feature tick icon Constantly refreshed with 50+ new titles a month
Feature tick icon Exclusive Early access to books as they're written
Feature tick icon Solve problems while you work with advanced search and reference features
Feature tick icon Offline reading on the mobile app
Feature tick icon Simple pricing, no contract
€189.99 billed annually
Feature tick icon Unlimited access to Packt's library of 7,000+ practical books and videos
Feature tick icon Constantly refreshed with 50+ new titles a month
Feature tick icon Exclusive Early access to books as they're written
Feature tick icon Solve problems while you work with advanced search and reference features
Feature tick icon Offline reading on the mobile app
Feature tick icon Choose a DRM-free eBook or Video every month to keep
Feature tick icon PLUS own as many other DRM-free eBooks or Videos as you like for just €5 each
Feature tick icon Exclusive print discounts
€264.99 billed in 18 months
Feature tick icon Unlimited access to Packt's library of 7,000+ practical books and videos
Feature tick icon Constantly refreshed with 50+ new titles a month
Feature tick icon Exclusive Early access to books as they're written
Feature tick icon Solve problems while you work with advanced search and reference features
Feature tick icon Offline reading on the mobile app
Feature tick icon Choose a DRM-free eBook or Video every month to keep
Feature tick icon PLUS own as many other DRM-free eBooks or Videos as you like for just €5 each
Feature tick icon Exclusive print discounts

Frequently bought together


Stars icon
Total 120.97
Learning C++ Functional Programming
€41.99
Mastering C++ Multithreading
€36.99
Modern C++ Programming Cookbook
€41.99
Total 120.97 Stars icon
Banner background image

Table of Contents

8 Chapters
Diving into Modern C++ Chevron down icon Chevron up icon
Manipulating Functions in Functional Programming Chevron down icon Chevron up icon
Applying Immutable State to the Function Chevron down icon Chevron up icon
Repeating Method Invocation Using Recursive Algorithm Chevron down icon Chevron up icon
Procrastinating the Execution Process Using Lazy Evaluation Chevron down icon Chevron up icon
Optimizing Code with Metaprogramming Chevron down icon Chevron up icon
Running Parallel Execution Using Concurrency Chevron down icon Chevron up icon
Creating and Debugging Application in Functional Approach Chevron down icon Chevron up icon

Customer reviews

Top Reviews
Rating distribution
Full star icon Full star icon Full star icon Half star icon Empty star icon 3.3
(6 Ratings)
5 star 16.7%
4 star 33.3%
3 star 33.3%
2 star 0%
1 star 16.7%
Filter icon Filter
Top Reviews

Filter reviews by




Christian Albaret Feb 16, 2024
Full star icon Full star icon Full star icon Full star icon Full star icon 5
I bought 5 books at once and could only give a fast glance at this one in order to write he review. It seems I have to write the reviews in order. I have been developping a lot in C++, and also used modern features of C++11 and above. The book discusses and shows examples on how to use these modern features. The advanced features are difficult to grasp: short examples don;t show enough, long examples are hard to read. The example in the book are fairly long, but they are given with detailed explanations.
Feefo Verified review Feefo
Mike Jan 05, 2018
Full star icon Full star icon Full star icon Full star icon Empty star icon 4
The grammar issue is bad but the author still manages to make himself understood. The content is decent but not worth the price.
Amazon Verified review Amazon
John Carter Sep 21, 2018
Full star icon Full star icon Full star icon Full star icon Empty star icon 4
Very difficult to get to get to grips with initially but gets easier as you go.
Amazon Verified review Amazon
Hangzhou Tang May 31, 2018
Full star icon Full star icon Full star icon Empty star icon Empty star icon 3
It's not as perfect as I assume before. I found an error even in the beginning of the book. For example in page 11, the book shows "auto main ->int" which should be "auto main() -> int".
Amazon Verified review Amazon
Jonathan Apr 22, 2018
Full star icon Full star icon Full star icon Empty star icon Empty star icon 3
Grammar is terrible. Code snippets are duplicated over and over again - concepts that can be shown in one or two lines are surrounded by 20 lines of boilerplate.Coming from functional programming languages, I was excited for what might be possible in c++ but was disappointed by the lack of depth in the book. I don't know enough about c++ to say that's the author's fault or the language's.
Amazon Verified review Amazon
Get free access to Packt library with over 7500+ books and video courses for 7 days!
Start Free Trial

FAQs

What is the delivery time and cost of print book? Chevron down icon Chevron up icon

Shipping Details

USA:

'

Economy: Delivery to most addresses in the US within 10-15 business days

Premium: Trackable Delivery to most addresses in the US within 3-8 business days

UK:

Economy: Delivery to most addresses in the U.K. within 7-9 business days.
Shipments are not trackable

Premium: Trackable delivery to most addresses in the U.K. within 3-4 business days!
Add one extra business day for deliveries to Northern Ireland and Scottish Highlands and islands

EU:

Premium: Trackable delivery to most EU destinations within 4-9 business days.

Australia:

Economy: Can deliver to P. O. Boxes and private residences.
Trackable service with delivery to addresses in Australia only.
Delivery time ranges from 7-9 business days for VIC and 8-10 business days for Interstate metro
Delivery time is up to 15 business days for remote areas of WA, NT & QLD.

Premium: Delivery to addresses in Australia only
Trackable delivery to most P. O. Boxes and private residences in Australia within 4-5 days based on the distance to a destination following dispatch.

India:

Premium: Delivery to most Indian addresses within 5-6 business days

Rest of the World:

Premium: Countries in the American continent: Trackable delivery to most countries within 4-7 business days

Asia:

Premium: Delivery to most Asian addresses within 5-9 business days

Disclaimer:
All orders received before 5 PM U.K time would start printing from the next business day. So the estimated delivery times start from the next day as well. Orders received after 5 PM U.K time (in our internal systems) on a business day or anytime on the weekend will begin printing the second to next business day. For example, an order placed at 11 AM today will begin printing tomorrow, whereas an order placed at 9 PM tonight will begin printing the day after tomorrow.


Unfortunately, due to several restrictions, we are unable to ship to the following countries:

  1. Afghanistan
  2. American Samoa
  3. Belarus
  4. Brunei Darussalam
  5. Central African Republic
  6. The Democratic Republic of Congo
  7. Eritrea
  8. Guinea-bissau
  9. Iran
  10. Lebanon
  11. Libiya Arab Jamahriya
  12. Somalia
  13. Sudan
  14. Russian Federation
  15. Syrian Arab Republic
  16. Ukraine
  17. Venezuela
What is custom duty/charge? Chevron down icon Chevron up icon

Customs duty are charges levied on goods when they cross international borders. It is a tax that is imposed on imported goods. These duties are charged by special authorities and bodies created by local governments and are meant to protect local industries, economies, and businesses.

Do I have to pay customs charges for the print book order? Chevron down icon Chevron up icon

The orders shipped to the countries that are listed under EU27 will not bear custom charges. They are paid by Packt as part of the order.

List of EU27 countries: www.gov.uk/eu-eea:

A custom duty or localized taxes may be applicable on the shipment and would be charged by the recipient country outside of the EU27 which should be paid by the customer and these duties are not included in the shipping charges been charged on the order.

How do I know my custom duty charges? Chevron down icon Chevron up icon

The amount of duty payable varies greatly depending on the imported goods, the country of origin and several other factors like the total invoice amount or dimensions like weight, and other such criteria applicable in your country.

For example:

  • If you live in Mexico, and the declared value of your ordered items is over $ 50, for you to receive a package, you will have to pay additional import tax of 19% which will be $ 9.50 to the courier service.
  • Whereas if you live in Turkey, and the declared value of your ordered items is over € 22, for you to receive a package, you will have to pay additional import tax of 18% which will be € 3.96 to the courier service.
How can I cancel my order? Chevron down icon Chevron up icon

Cancellation Policy for Published Printed Books:

You can cancel any order within 1 hour of placing the order. Simply contact customercare@packt.com with your order details or payment transaction id. If your order has already started the shipment process, we will do our best to stop it. However, if it is already on the way to you then when you receive it, you can contact us at customercare@packt.com using the returns and refund process.

Please understand that Packt Publishing cannot provide refunds or cancel any order except for the cases described in our Return Policy (i.e. Packt Publishing agrees to replace your printed book because it arrives damaged or material defect in book), Packt Publishing will not accept returns.

What is your returns and refunds policy? Chevron down icon Chevron up icon

Return Policy:

We want you to be happy with your purchase from Packtpub.com. We will not hassle you with returning print books to us. If the print book you receive from us is incorrect, damaged, doesn't work or is unacceptably late, please contact Customer Relations Team on customercare@packt.com with the order number and issue details as explained below:

  1. If you ordered (eBook, Video or Print Book) incorrectly or accidentally, please contact Customer Relations Team on customercare@packt.com within one hour of placing the order and we will replace/refund you the item cost.
  2. Sadly, if your eBook or Video file is faulty or a fault occurs during the eBook or Video being made available to you, i.e. during download then you should contact Customer Relations Team within 14 days of purchase on customercare@packt.com who will be able to resolve this issue for you.
  3. You will have a choice of replacement or refund of the problem items.(damaged, defective or incorrect)
  4. Once Customer Care Team confirms that you will be refunded, you should receive the refund within 10 to 12 working days.
  5. If you are only requesting a refund of one book from a multiple order, then we will refund you the appropriate single item.
  6. Where the items were shipped under a free shipping offer, there will be no shipping costs to refund.

On the off chance your printed book arrives damaged, with book material defect, contact our Customer Relation Team on customercare@packt.com within 14 days of receipt of the book with appropriate evidence of damage and we will work with you to secure a replacement copy, if necessary. Please note that each printed book you order from us is individually made by Packt's professional book-printing partner which is on a print-on-demand basis.

What tax is charged? Chevron down icon Chevron up icon

Currently, no tax is charged on the purchase of any print book (subject to change based on the laws and regulations). A localized VAT fee is charged only to our European and UK customers on eBooks, Video and subscriptions that they buy. GST is charged to Indian customers for eBooks and video purchases.

What payment methods can I use? Chevron down icon Chevron up icon

You can pay with the following card types:

  1. Visa Debit
  2. Visa Credit
  3. MasterCard
  4. PayPal
What is the delivery time and cost of print books? Chevron down icon Chevron up icon

Shipping Details

USA:

'

Economy: Delivery to most addresses in the US within 10-15 business days

Premium: Trackable Delivery to most addresses in the US within 3-8 business days

UK:

Economy: Delivery to most addresses in the U.K. within 7-9 business days.
Shipments are not trackable

Premium: Trackable delivery to most addresses in the U.K. within 3-4 business days!
Add one extra business day for deliveries to Northern Ireland and Scottish Highlands and islands

EU:

Premium: Trackable delivery to most EU destinations within 4-9 business days.

Australia:

Economy: Can deliver to P. O. Boxes and private residences.
Trackable service with delivery to addresses in Australia only.
Delivery time ranges from 7-9 business days for VIC and 8-10 business days for Interstate metro
Delivery time is up to 15 business days for remote areas of WA, NT & QLD.

Premium: Delivery to addresses in Australia only
Trackable delivery to most P. O. Boxes and private residences in Australia within 4-5 days based on the distance to a destination following dispatch.

India:

Premium: Delivery to most Indian addresses within 5-6 business days

Rest of the World:

Premium: Countries in the American continent: Trackable delivery to most countries within 4-7 business days

Asia:

Premium: Delivery to most Asian addresses within 5-9 business days

Disclaimer:
All orders received before 5 PM U.K time would start printing from the next business day. So the estimated delivery times start from the next day as well. Orders received after 5 PM U.K time (in our internal systems) on a business day or anytime on the weekend will begin printing the second to next business day. For example, an order placed at 11 AM today will begin printing tomorrow, whereas an order placed at 9 PM tonight will begin printing the day after tomorrow.


Unfortunately, due to several restrictions, we are unable to ship to the following countries:

  1. Afghanistan
  2. American Samoa
  3. Belarus
  4. Brunei Darussalam
  5. Central African Republic
  6. The Democratic Republic of Congo
  7. Eritrea
  8. Guinea-bissau
  9. Iran
  10. Lebanon
  11. Libiya Arab Jamahriya
  12. Somalia
  13. Sudan
  14. Russian Federation
  15. Syrian Arab Republic
  16. Ukraine
  17. Venezuela