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C++ High Performance

You're reading from   C++ High Performance Master the art of optimizing the functioning of your C++ code

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Product type Paperback
Published in Dec 2020
Publisher Packt
ISBN-13 9781839216541
Length 544 pages
Edition 2nd Edition
Languages
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Authors (2):
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Viktor Sehr Viktor Sehr
Author Profile Icon Viktor Sehr
Viktor Sehr
Björn Andrist Björn Andrist
Author Profile Icon Björn Andrist
Björn Andrist
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Toc

Table of Contents (17) Chapters Close

Preface 1. A Brief Introduction to C++ 2. Essential C++ Techniques FREE CHAPTER 3. Analyzing and Measuring Performance 4. Data Structures 5. Algorithms 6. Ranges and Views 7. Memory Management 8. Compile-Time Programming 9. Essential Utilities 10. Proxy Objects and Lazy Evaluation 11. Concurrency 12. Coroutines and Lazy Generators 13. Asynchronous Programming with Coroutines 14. Parallel Algorithms 15. Other Books You May Enjoy
16. Index

Avoiding constructing objects using proxy objects

Eager evaluation can have the undesirable effect that objects are unnecessarily constructed. Often this is not a problem, but if the objects are expensive to construct (because of heap allocations, for example), there might be legitimate reasons to optimize away the unnecessary construction of short-lived objects that serve no purpose.

Comparing concatenated strings using a proxy

We will now walk through a minimal example of using proxy objects to give you an idea of what they are and can be used for. It's not meant to provide you with a general production-ready solution to optimizing string comparisons.

With that said, take a look at this code snippet that concatenates two strings and compares the result:

auto a = std::string{"Cole"}; 
auto b = std::string{"Porter"}; 
auto c = std::string{"ColePorter"}; 
auto is_equal = (a + b) == c;        // true

Here is a visual representation...

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