C++17 structured bindings causing implementing const references in loop
I keep running into I'm confused about I'm experiencing an scenario with structured bindings in C++17 when trying to iterate over a map of `std::pair<const Key, Value>`. While attempting to use a range-based for loop, I noticed that the keys are being treated as non-const when destructured, leading to unexpected behavior. Here’s a simplified version of my code: ```cpp #include <iostream> #include <map> int main() { std::map<int, std::string> myMap = {{1, "One"}, {2, "Two"}, {3, "Three"}}; for (auto [key, value] : myMap) { key = 10; // This line should not compile or modify the key std::cout << "Key: " << key << ", Value: " << value << std::endl; } return 0; } ``` When I attempt to compile this, I receive the following behavior message: ``` behavior: want to assign to variable 'key' with const-qualified type 'const int' ``` I initially thought structured bindings would handle the constness appropriately, allowing me to work with the keys as immutable. I’ve tried changing my loop to use `const auto&` for both the key and value like this: ```cpp for (const auto& [key, value] : myMap) { // some operations } ``` But I still get the same behavior when I attempt to assign to `key`. Is there a way to correctly use structured bindings with const references in this context, or is there a best practice for iterating over maps that can prevent this confusion? Thanks for any insights! My development environment is macOS. How would you solve this? How would you solve this? I'm working in a Ubuntu 22.04 environment. Any examples would be super helpful. Hoping someone can shed some light on this.