当我根据每个单元格的状态更新其颜色时,我观察到两个循环之间存在巨大的性能差异:一个使用向量的迭代器,另一个使用index-based方法。 以下是差异出现的地方: inline void ChangeCellColor(Cell& cell, sf::Color color) { // index-based loop auto index = cell.grid_y * width_ + cell.grid_x; for (i...
range-basedforloop在内部使用迭代器，但它不会向您公开这些迭代器。因此，在第一个方法中，i根本不是...
Let's test them with the range-based for loop: Integers integers; for (auto i : integers) std::cout << i << "\n"; This code will magically print the value of each integer in the container. It works because the range-based for loop is just syntactic sugar created by the compiler...
What you’re trying to do is “save” the position ofdirIterator, but (via the range-based for-loop, which is merely a syntax convenience for copying the iterator) you’re advancing the iterator. Input-only iterators don’t permit this - you don’t really get differen...
1 ['a', 'c', 'e'] 2 ['b', 'd', 'f'] 3 ['g'] This more complicated example illustrates grouping related values based on some attribute. Notice that the input sequence needs to be sorted on the key in order for the groupings to work out as expected. ...
In the example above, the compiler knows the type of it based on the return type of cars.begin(), which is vector<string>::iterator.The auto keyword works in for loops as well:for (auto it = cars.begin(); it != cars.end(); ++it) { cout << *it << "\n";} Try it ...
range-based for loop support (function) Additionally, operator== and operator!= are provided, either as members or as non-members, as required by InputIterator Example #include <fstream> #include <iostream> #include <experimental/filesystem> namespace fs = std::experimental::filesystem; ...
#include <iostream> #include <filesystem> #include <string> int main() { auto iterator = std::filesystem::directory_iterator("c:/somefolder"); for (auto& i : iterator) { i.exists(); i.file_size(); } } 我将range-based循环理解为“对于迭代器中的每个i,调用i.file_size()” 的操...
reference说明:Aforexpression is a syntactic construct for looping over elements provided by an implementation ofstd::iter::IntoIterator。 Iterator有丰富的API及其默认实现,具体可以参考标准库文档 Iterators The power offor Rust'sforloop is safer, more powerful, and more efficient than C's. For exampl...
Changes fromall commits File filter Conversations Jump to Apply and reload Show whitespace 7 changes: 7 additions & 0 deletions7src/Runtime/LoopIterator.php Original file line numberDiff line numberDiff line change Expand Up@@ -19,6 +19,10 @@ ...