Book Image

C++20 STL Cookbook

By : Bill Weinman
Book Image

C++20 STL Cookbook

By: Bill Weinman

Overview of this book

Fast, efficient, and flexible, the C++ programming language has come a long way and is used in every area of the industry to solve many problems. The latest version C++20 will see programmers change the way they code as it brings a whole array of features enabling the quick deployment of applications. This book will get you up and running with using the STL in the best way possible. Beginning with new language features in C++20, this book will help you understand the language's mechanics and library features and offer insights into how they work. Unlike other books, the C++20 STL Cookbook takes an implementation-specific, problem-solution approach that will help you overcome hurdles quickly. You'll learn core STL concepts, such as containers, algorithms, utility classes, lambda expressions, iterators, and more, while working on real-world recipes. This book is a reference guide for using the C++ STL with its latest capabilities and exploring the cutting-edge features in functional programming and lambda expressions. By the end of the book C++20 book, you'll be able to leverage the latest C++ features and save time and effort while solving tasks elegantly using the STL.
Table of Contents (13 chapters)

Initialize complex structures from file input

One strength of the input stream is its ability to parse different types of data from a text file and convert them to their corresponding fundamental types. Here's a simple technique for importing data into a container of structures using an input stream.

How to do it…

In this recipe, we'll take a data file and import its disparate fields into a vector of struct objects. The data file represents cities with their populations and map coordinates:

  • This is cities.txt, the data file we'll read:
    Las Vegas
    661903 36.1699 -115.1398
    New York City
    8850000 40.7128 -74.0060
    3571000 52.5200 13.4050
    Mexico City
    21900000 19.4326 -99.1332
    5312000 -33.8688 151.2093

The city name is on a line by itself. The second line is population, followed by longitude and latitude. This pattern repeats for each of the five cities.

  • We'll define our filename in a constant so that we can open it later...