Book Image

Boost C++ Application Development Cookbook - Second Edition

By : Anton Polukhin Alekseevic
Book Image

Boost C++ Application Development Cookbook - Second Edition

By: Anton Polukhin Alekseevic

Overview of this book

If you want to take advantage of the real power of Boost and C++ and avoid the confusion about which library to use in which situation, then this book is for you. Beginning with the basics of Boost C++, you will move on to learn how the Boost libraries simplify application development. You will learn to convert data such as string to numbers, numbers to string, numbers to numbers and more. Managing resources will become a piece of cake. You’ll see what kind of work can be done at compile time and what Boost containers can do. You will learn everything for the development of high quality fast and portable applications. Write a program once and then you can use it on Linux, Windows, MacOS, Android operating systems. From manipulating images to graphs, directories, timers, files, networking – everyone will find an interesting topic. Be sure that knowledge from this book won’t get outdated, as more and more Boost libraries become part of the C++ Standard.
Table of Contents (19 chapters)
Title Page
Credits
About the Author
About the Reviewer
www.PacktPub.com
Customer Feedback
Preface

Converting strings to numbers


Converting strings to numbers in C++ makes a lot of people depressed because of their inefficiency and user unfriendliness. See how string 100 can be converted to int:

#include <sstream> 

void sample1() {
    std::istringstream iss("100");
    int i;
    iss >> i;

    // ...
}

It is better not to think, how many unnecessary operations, virtual function calls, atomic operations, and memory allocations occurred during the conversion from earlier. By the way, we do not need the iss variable any more, but it will be alive until the end of scope.

C methods are not much better:

#include <cstdlib> 

void sample2() {
    char * end;
    const int i = std::strtol ("100", &end, 10);

    // ...
}

Did it convert the whole value to int or stopped somewhere in the middle? To understand that we must check the content of the end variable. After that we'll have a useless end variable getting in the way until the end of scope. And we wanted an int, but strtol...