requires expression Concept (named requirements) // OK, uses 1st add() calling push_back() // OK, uses 2nd add() calling insert() Nico Josuttis C++ Concepts @cppcon 2024-09-18 3©2024 by josuttis.com 7 C++ coll2; add(coll1, 42); // OK, uses 1st add() calling push_back() add(coll2, 42); // OK, uses 2nd add() calling insert() C++20 C++20 Type Constraints with concepts applied to types Requirements 42); add(coll2, 42); // C++20 C++20 // ERROR: "can't call insert()" // OK, uses 2nd add() calling insert() 2nd add() is used, because concept for 1st add() not satisfied Requirements not met =>

eax, edi shl eax, 4 add eax, esi ret ... Flush, update branch history, refetchExample – branching, 2nd attempt 72 uint32_t fn(uint32_t x, uint32_t y, size_t cond) { if (cond == 27) return (x << 4) 89 F8 C1 E0 04 01 F0 EB 06 89 F8 D1 E8 29 F0 C3 66 66 0F 1F 84 00 00 00 00 00Example – branching, 2nd attempt 73 uint32_t fn(uint32_t x, uint32_t y, size_t cond) { if (cond == 27) return (x << 4) 89 F8 C1 E0 04 01 F0 EB 06 89 F8 D1 E8 29 F0 C3 66 66 0F 1F 84 00 00 00 00 00Example – branching, 2nd attempt 74 uint32_t fn(uint32_t x, uint32_t y, size_t cond) { if (cond == 27) return (x << 4)

the 2nd function: f(1.1, 2, 3); // calls f(double, int, double)  The conversions are the same for both functions on the 1st and 3rd arguments.  The 2nd function is a better match on the 2nd (middle)

Object-Oriented Software Construction (2nd ed.)Meyer OPC: Adapting a Module to New Clients (After) Meyer, B. (1997). Object-Oriented Software Construction (2nd ed.)OCP in C++: Strong and Weak Principles

<< '\n'; } // print every 2nd element (array, vector, deque only): for (auto pos = coll.begin(); pos < coll.end(); pos += 2) { std::cout << *pos << '\n'; } // print every 2nd element (for all containers):

user group Chair of the CppCon Back-to-Basics track Email: klaus.iglberger@gmx.deThe 2nd in a Row 3The 2nd in a Row 45 Let’s again talk about design patterns and virtual functionsThe Overhead

// OK, calls 2nd print() print(vec | std::views::filter(gt9)); // OK, calls 1st print() print(getColl()); // OK, calls 2nd print() print(getColl() | s

location in an output array from a small number of points in an input array. In our benchmark we use the 2nd order Laplace operator: ∀i,j : yij ← 4xij −xi−1,j −xi+1,j −xi, j−1 −xi,j+1 where i, j can jointly

Replica/Partition Allocator Pod A-1 Pod A-2 Pod A-3 Pod A-4 Pod A-5 Beta Group 1st Group 2nd Group InPlaceSet A CafeDeployment partition:1 …… Pod Upgrade 机房A – 单元A • 精准分组，自定义拓扑 • IP不变，无损升级

feature requests Come chat with us about future ideas and what you’d like to see!Our sessions Monday 2nd • Lifetime Safety in C++ – Gabor Horvath • Informal Birds of a Feather for Cpp2/cppfront – Herb Sutter