Search icon CANCEL
Subscription
0
Cart icon
Your Cart (0 item)
Close icon
You have no products in your basket yet
Save more on your purchases now! discount-offer-chevron-icon
Savings automatically calculated. No voucher code required.
Arrow left icon
Explore Products
Best Sellers
New Releases
Books
Videos
Audiobooks
Learning Hub
Conferences
Free Learning
Arrow right icon
Mastering the C++17 STL
Mastering the C++17 STL

Mastering the C++17 STL: Make full use of the standard library components in C++17

Arrow left icon
Profile Icon Arthur O'Dwyer
Arrow right icon
€36.99
Paperback Sep 2017 384 pages 1st Edition
eBook
€20.98 €29.99
Paperback
€36.99
Subscription
Free Trial
Renews at €18.99p/m
Arrow left icon
Profile Icon Arthur O'Dwyer
Arrow right icon
€36.99
Paperback Sep 2017 384 pages 1st Edition
eBook
€20.98 €29.99
Paperback
€36.99
Subscription
Free Trial
Renews at €18.99p/m
eBook
€20.98 €29.99
Paperback
€36.99
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
Table of content icon View table of contents Preview book icon Preview Book

Mastering the C++17 STL

Iterators and Ranges

In the previous chapter, we implemented several generic algorithms that operated on containers, but in an inefficient manner. In this chapter, you'll learn:

  • How and why C++ generalizes the idea of pointers to create the iterator concept
  • The importance of ranges in C++, and the standard way to express a half-open range as a pair of iterators
  • How to write your own rock-solid, const-correct iterator types
  • How to write generic algorithms that operate on iterator pairs
  • The standard iterator hierarchy and its algorithmic importance

The problem with integer indices

In the previous chapter, we implemented several generic algorithms that operated on containers. Consider one of those algorithms again:

    template<typename Container>
void double_each_element(Container& arr)
{
for (int i=0; i < arr.size(); ++i) {
arr.at(i) *= 2;
}
}

This algorithm is defined in terms of the lower-level operations .size() and .at(). This works reasonably well for a container type such as array_of_ints or std::vector, but it doesn't work nearly so well for, say, a linked list such as the previous chapter's list_of_ints:

    class list_of_ints {
struct node {
int data;
node *next;
};
node *head_ = nullptr;
node *tail_ = nullptr;
int size_ = 0;
public:
int size() const { return size_; }
int& at(int i) {
if (i >= size_...

On beyond pointers

In the absence of any abstraction, how does one normally identify an element of an array, an element of a linked list, or an element of a tree? The most straightforward way would be to use a pointer to the element's address in memory. Here are some examples of pointers to elements of various data structures:

To iterate over an array, all we need is that pointer; we can handle all the elements in the array by starting with a pointer to the first element and simply incrementing that pointer until it reaches the last element. In C:

    for (node *p = lst.head_; p != nullptr; p = p->next) {
if (pred(p->data)) {
sum += 1;
}
}

But in order to efficiently iterate over a linked list, we need more than just a raw pointer; incrementing a pointer of type node* is highly unlikely to produce a pointer to the next node in the list! In that case...

Const iterators

There's just one more complication to consider, before we abandon this list iterator example. Notice that I quietly changed our count_if function template so that it takes Container& instead of const Container&! That's because the begin() and end() member functions we provided are non-const member functions; and that's because they return iterators whose operator* returns non-const references to the elements of the list. We'd like to make our list type (and its iterators) completely const-correct--that is, we'd like you to be able to define and use variables of type const list_of_ints, but prevent you from modifying the elements of a const list.

The standard library generally deals with this issue by giving each standard container two different kinds of iterator: bag::iterator and bag::const_iterator. The non-const member function...

A pair of iterators defines a range

Now that we understand the fundamental concept of an iterator, let's put it to some practical use. We've already seen that if you have a pair of iterators as returned from begin() and end(), you can use a for-loop to iterate over all the elements of the underlying container. But more powerfully, you can use some pair of iterators to iterate over any sub-range of the container's elements! Let's say you only wanted to view the first half of a vector:

    template<class Iterator>
void double_each_element(Iterator begin, Iterator end)
{
for (auto it = begin; it != end; ++it) {
*it *= 2;
}
}

int main()
{
std::vector<int> v {1, 2, 3, 4, 5, 6};
double_each_element(v.begin(), v.end());
// double each element in the entire vector
double_each_element(v.begin(), v...

Iterator categories

Let's revisit the count and count_if functions that we introduced in
Chapter 1, Classical Polymorphism and Generic Programming. Compare the function template definition in this next example to the similar code from that chapter; you'll see that it's identical except for the substitution of a pair of Iterators (that is, an implicitly defined range) for the Container& parameter--and except that I've changed the name of the first function from count to distance. That's because you can find this function, almost exactly as described here, in the Standard Template Library under the name std::distance and you can find the second function under the name std::count_if:

    template<typename Iterator>
int distance(Iterator begin, Iterator end)
{
int sum = 0;
for (auto it = begin; it != end; ++it) {
sum += 1...

Input and output iterators

We can imagine even weaker concepts than ForwardIterator! For example, one useful thing you can do with a ForwardIterator is to make a copy of it, save the copy, and use it to iterate twice over the same data. Manipulating the iterator (or copies of it) doesn't affect the underlying range of data at all. But we could invent an iterator like the one in the following snippet, where there is no underlying data at all, and it's not even meaningful to make a copy of the iterator:

    class getc_iterator {
char ch;
public:
getc_iterator() : ch(getc(stdin)) {}
char operator*() const { return ch; }
auto& operator++() { ch = getc(stdin); return *this; }
auto operator++(int) { auto result(*this); ++*this; return result; }
bool operator==(const getc_iterator&) const { return false; }
bool operator!=(const...

Putting it all together

Putting together everything we've learned in this chapter, we can now write code like the following example. In this example, we're implementing our own list_of_ints with our own iterator class (including a const-correct const_iterator version); and we're enabling it to work with the standard library by providing the five all-important member typedefs.

    struct list_node {
int data;
list_node *next;
};

template<bool Const>
class list_of_ints_iterator {
friend class list_of_ints;
friend class list_of_ints_iterator<!Const>;

using node_pointer = std::conditional_t<Const, const list_node*,
list_node*>;
node_pointer ptr_;

explicit list_of_ints_iterator(node_pointer p) : ptr_(p) {}
public:
// Member typedefs required by std::iterator_traits
using difference_type...

The deprecated std::iterator

You might be wondering: "Every iterator class I implement needs to provide the same five member typedefs. That's a lot of boilerplate--a lot of typing that I'd like to factor out, if I could." Is there no way to eliminate all that boilerplate?

Well, in C++98, and up until C++17, the standard library included a helper class template to do exactly that. Its name was std::iterator, and it took five template type parameters that corresponded to the five member typedefs required by std::iterator_traits. Three of these parameters had "sensible defaults," meaning that the simplest use-case was pretty well covered:

    namespace std {
template<
class Category,
class T,
class Distance = std::ptrdiff_t,
class Pointer = T*,
class Reference = T&
> struct iterator {
using...

Summary

In this chapter, we've learned that traversal is one of the most fundamental things you can do with a data structure. However, raw pointers alone are insufficient for traversing complicated structures: applying ++ to a raw pointer often doesn't "go on to the next item" in the intended way.

The C++ Standard Template Library provides the concept of iterator as a generalization of raw pointers. Two iterators define a range of data. That range might be only part of the contents of a container; or it might be unbacked by any memory at all, as we saw with getc_iterator and putc_iterator. Some of the properties of an iterator type are encoded in its iterator category--input, output, forward, bidirectional, or random-access--for the benefit of function templates that can use faster algorithms on certain categories of iterators.

If you're defining your...

Left arrow icon Right arrow icon
Download code icon Download Code

Key benefits

  • Boost your productivity as a C++ developer with the latest features of C++17
  • Develop high-quality, fast, and portable applications with the varied features of the STL
  • Migrate from older versions (C++11, C++14) to C++17

Description

Modern C++ has come a long way since 2011. The latest update, C++17, has just been ratified and several implementations are on the way. This book is your guide to the C++ standard library, including the very latest C++17 features. The book starts by exploring the C++ Standard Template Library in depth. You will learn the key differences between classical polymorphism and generic programming, the foundation of the STL. You will also learn how to use the various algorithms and containers in the STL to suit your programming needs. The next module delves into the tools of modern C++. Here you will learn about algebraic types such as std::optional, vocabulary types such as std::function, smart pointers, and synchronization primitives such as std::atomic and std::mutex. In the final module, you will learn about C++'s support for regular expressions and file I/O. By the end of the book you will be proficient in using the C++17 standard library to implement real programs, and you'll have gained a solid understanding of the library's own internals.

Who is this book for?

This book is for developers who would like to master the C++ STL and make full use of its components. Prior C++ knowledge is assumed.

What you will learn

  • - Make your own iterator types, allocators, and thread pools.
  • - Master every standard container and every standard algorithm.
  • - Improve your code by replacing new/delete with smart pointers.
  • - Understand the difference between monomorphic algorithms, polymorphic algorithms, and generic algorithms.
  • - Learn the meaning and applications of vocabulary type, product type and sum type.
Estimated delivery fee Deliver to Cyprus

Premium delivery 7 - 10 business days

€32.95
(Includes tracking information)

Product Details

Country selected
Publication date, Length, Edition, Language, ISBN-13
Publication date : Sep 28, 2017
Length: 384 pages
Edition : 1st
Language : English
ISBN-13 : 9781787126824
Category :
Languages :
Tools :

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
Estimated delivery fee Deliver to Cyprus

Premium delivery 7 - 10 business days

€32.95
(Includes tracking information)

Product Details

Publication date : Sep 28, 2017
Length: 384 pages
Edition : 1st
Language : English
ISBN-13 : 9781787126824
Category :
Languages :
Tools :

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 115.97
Mastering the C++17 STL
€36.99
Mastering C++ Multithreading
€36.99
C++17 STL Cookbook
€41.99
Total 115.97 Stars icon

Table of Contents

12 Chapters
Classical Polymorphism and Generic Programming Chevron down icon Chevron up icon
Iterators and Ranges Chevron down icon Chevron up icon
The Iterator-Pair Algorithms Chevron down icon Chevron up icon
The Container Zoo Chevron down icon Chevron up icon
Vocabulary Types Chevron down icon Chevron up icon
Smart Pointers Chevron down icon Chevron up icon
Concurrency Chevron down icon Chevron up icon
Allocators Chevron down icon Chevron up icon
Iostreams Chevron down icon Chevron up icon
Regular Expressions Chevron down icon Chevron up icon
Random Numbers Chevron down icon Chevron up icon
Filesystem Chevron down icon Chevron up icon
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