C++ 2017 Online

std::map<int, std::string> m = 1, "a"; for (const auto& [key, val] : m) // key = 1, val = "a" std::cout << key << ": " << val << '\n';

std::map<int, std::string> src1,"a"; std::map<int, std::string> dst; dst.insert(src.extract(1)); Distinct enum class for raw memory representation (no arithmetic). c++ 2017

// in a header inline int global_counter = 0; Mandates copy elision for prvalues, making certain moves/constructors unnecessary even conceptually. std::map&lt;int, std::string&gt; m = 1, "a"; for (const

if (auto it = m.find(key); it != m.end()) // use it here // it goes out of scope Permits defining variables in header files without violating the One Definition Rule (ODR). Essential for header-only libraries. for (const auto& [key