Hash tables

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Before C++11, hash tables could be used in C++ only with some tricks. The only associative container available in the STL used to be the std::map (along with its sibling, the multimap). This class, however, is implemented as a binary search tree, and does not provide a way to customize a hash function. What hurt me most was that you didn’t have the great performances offered by a true hash map: almost constant time insert, delete, and search (depending on how good is the hash function). You insert in O(log N) time. You find in O(log N) time. Too bad.

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Accessing APIs

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I was curious about all the great sites I know of releasing their API. Twitter, Google, Facebook, Yelp, are only a few examples of websites providing a way to access their services in a programmatic way. In this post, I have investigated a simple but very interesting API, offered by Rotten Tomatoes, a website about movies.

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Use files

This post has been created more than 3 months ago. It might contain inaccurate or stale (or both!) information. Use with caution!

Recently I’ve found myself in the common situation where I have to open a file and make something with its content. This is a basic task and should present no difficulties to a programmer; I happened, however, to get stuck for a while in search of a good way to carry out this apparently simple task. In particular, I have run into the recent addition of regular expression processing to the STL. Spoiler alert: I was not particularly happy of what I’ve found along the way.

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Time in C++

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Using time: the chrono header

Until before the introduction of the chrono library in the STL with the C++11 standard, we were forced to deal with time in a couple of ways, notably using Boost or using some wrapper around the time.h library header, from C.

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STL Algorithms, part 4

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We have seen some examples of usage of the find algorithm, with its variants find_if and find_if_not. In this installment, we are going to see other variants of finding algorithms, plus another algorithm useful when counting items in a sequence, count. Remember that we are still in the realm of non-modifying sequence algorithms (but see the discussion about for_each here).

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STL Algorithms, part 3

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In the previous posts of this series, we have had a glance at non-modifying sequence algorithms, i.e., the algorithms that are supposed not to modify the elements of a sequence (or at least, the structure of the sequence; see the observations about for_each.

In this installment, as anticipated, we will start looking at the algorithms for searching.

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STL Algorithms, part 2

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Previously on this blog

In the previous installment, we have introduced three algorithms, all_of, any_of, and none_of, very useful to determine whether a range of elements satisfy some predicate, expressed as a lambda.

In this second episode, we will explore more algorithms offered by the STL. My objective, in the long run, is to cover all of them with examples, and maybe grasp the ideas that might come to my mind during the process. As usual, if you have any doubt or just spot a plain error, I’d greatly appreciate if you let me know.

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STL Algorithms, part 1

This post has been created more than 3 months ago. It might contain inaccurate or stale (or both!) information. Use with caution!

Why algorithms

Standard algorithms have a prominent value in the C++ standard template library (STL). They present the great advantage of expressing an operation applied on a range of elements in a container. In this series, I am going to review all the algorithms introduced in the C++11 standard, presenting it in digestible chunks, and will provide at least an example of application for each one.

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