std::map iterators invalidated unexpectedly after insertion in C++20
I'm converting an old project and I've been struggling with this for a few days now and could really use some help..... I've been working on this all day and I'm reviewing some code and I am working with an scenario with `std::map` where I am seeing an unexpected behavior regarding iterator invalidation after inserting elements. I'm using C++20 and trying to maintain a sorted map of integers. The main concern arises when I attempt to iterate over the map after performing insertions. Here’s a simplified version of my code: ```cpp #include <iostream> #include <map> int main() { std::map<int, std::string> myMap; myMap.insert({1, "One"}); myMap.insert({2, "Two"}); myMap.insert({3, "Three"}); // Create an iterator to the first element auto it = myMap.begin(); std::cout << "First element: " << it->first << " - " << it->second << '\n'; // Now let's insert a new element myMap.insert({4, "Four"}); // Access the iterator after insertion std::cout << "After insertion: " << it->first << " - " << it->second << '\n'; // This line throws an behavior return 0; } ``` When I run the code, I get the following behavior: ``` terminate called after throwing an instance of 'std::out_of_range' what(): map::at: key not found ``` I expected that iterators of `std::map` would remain valid after insertions, considering that `std::map` maintains its structure without invalidating existing iterators (unless the key being pointed to is removed directly). Am I misunderstanding something about how insertions work in `std::map`, or is there some other underlying scenario? I've checked the C++20 standard, and it states that insertions should not invalidate iterators unless an element is removed. Any insights or suggestions for resolving this scenario would be greatly appreciated. My development environment is Windows. I'm working on a mobile app that needs to handle this. I recently upgraded to C++ stable. Thanks in advance! This is for a service running on Windows 10. Cheers for any assistance! My team is using C++ for this CLI tool. Thanks, I really appreciate it!