Difference between revisions of "Intermediate C++ Game Programming Tutorial 16"
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== <span style="color:red">Errata</span> == | == <span style="color:red">Errata</span> == | ||
In the video Chili states that std::remove does not preserve the relative order of elements in the container, but this is fake news! Relative order is preserved: [https://en.cppreference.com/w/cpp/algorithm/remove] | In the video Chili states that std::remove does not preserve the relative order of elements in the container, but this is fake news! Relative order is preserved: [https://en.cppreference.com/w/cpp/algorithm/remove] | ||
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| + | In the homework solution there is a part where Chili uses an iterator into a <code>stringstream</code> [https://youtu.be/_1-iES-Eytc?t=626]. This code no longer works due to changes (improvements) to the Visual Studio compiler. Basically, you cannot pass a temporary stream into the iterator constructor. See this: [https://stackoverflow.com/questions/23714445/passing-temporary-istringstream-object-to-istream-iteratorstring] | ||
== Video Timestamp Index == | == Video Timestamp Index == | ||
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Solve the problems in Source.cpp attached below using the <algorithm> library and other parts of the standard library as extensively as possible. As a bonus problem, implement the sprite drawing effect shown at the end of the video using a lambda function. | Solve the problems in Source.cpp attached below using the <algorithm> library and other parts of the standard library as extensively as possible. As a bonus problem, implement the sprite drawing effect shown at the end of the video using a lambda function. | ||
| − | * [ | + | * [https://www.planetchili.net/downloads/I16-HW.zip Source.cpp (homework file)] |
* [https://github.com/planetchili/sprite Sprite Repo (for bonus problem)] | * [https://github.com/planetchili/sprite Sprite Repo (for bonus problem)] | ||
Latest revision as of 13:26, 5 May 2022
In the video we take a look at a couple of bangers from <algorithm>, and we learn what lambda functions are and how to use them.
Contents
Topics Covered
- Algorithms
std::sortandstd::remove_if - Concepts (as in, type concepts like Comparable)
-
<functional>functors as predicates - Lambda functions
Errata
In the video Chili states that std::remove does not preserve the relative order of elements in the container, but this is fake news! Relative order is preserved: [1]
In the homework solution there is a part where Chili uses an iterator into a stringstream [2]. This code no longer works due to changes (improvements) to the Visual Studio compiler. Basically, you cannot pass a temporary stream into the iterator constructor. See this: [3]
Video Timestamp Index
- Generic Algorithms: how Templates and Iterators make Algorithms independent of Data Types and Containers 0:17
- The
std::sortalgorithm and its requirements 0:43 - Sorting a (forward) list
std::list, using its member functionstd::list::sort()2:16 - Introducing Concepts / named requirements of types (e.g., the
Comparerequirement ofstd::sort) 2:54 - Modyfing sorting order by passing a comparison function object (functor) as a predicate, like so:
std::sort(vec.begin(),vec.end(),std::greater<int>{});3:17
Note: vec is a std::vector of integers - Sort custom types, example code for sorting a custom class object by creating a functor, called like so:
std::sort(vecObj.begin(),vecObj.end(),Obj::YLess{});4:07 - Removing items from a container,
std::removeandstd::remove_if6:11
- Introducing Lambda functions to replace custom functors 11:51
- Using the Lambda capture to bring in variables into the Lambda function 13:34
- Capture syntax explained:
[var],[&var],[=],[&],[newvar=var+10],[this], capture multiple variables, mix&match capture modes - Stateful Lambdas; changing captured lambda variables using the
mutableflag 15:59
- Capture syntax explained:
- Make it callable once:
[...](...){...}(vec.front());, functor is destroyed immediately - Keep the functor using
auto mylamb = [...](...){...};, which can be called bybool result = mylamb(vec.front());, orstd::remove_if(...,...,mylamb);
- Make it callable once:
Homework
Solve the problems in Source.cpp attached below using the <algorithm> library and other parts of the standard library as extensively as possible. As a bonus problem, implement the sprite drawing effect shown at the end of the video using a lambda function.
The homework solution video can be found here
Related Series
For an in-depth look into the <algorithm> library and beyond, check out STD Gems.
