Unexpected behavior when using std::optional with emplace in C++20
I'm a bit lost with After trying multiple solutions online, I still can't figure this out... I tried several approaches but none seem to work. I'm encountering unexpected behavior when using `std::optional` combined with `emplace` in C++20. I have a class that holds an `std::optional` member, and I want to construct an object in place when calling a method. However, I'm seeing that the optional is not being initialized as expected. Here's a simplified version of my code: ```cpp #include <iostream> #include <optional> #include <string> class MyClass { public: std::optional<std::string> name; void setName(const std::string& newName) { name.emplace(newName); } }; int main() { MyClass obj; obj.setName("Alice"); if (obj.name) { std::cout << "Name: " << *obj.name << std::endl; } else { std::cout << "Name is not set." << std::endl; } return 0; } ``` I originally thought that this code would always set `name` to "Alice", but when I run it, I get the output "Name: Alice" as expected. However, when I modify the method to check for the existence of the optional before setting it, like this: ```cpp void setName(const std::string& newName) { if (!name) { name.emplace(newName); } } ``` Now, when I try to set the name again (e.g., `obj.setName("Bob");` after calling `obj.setName("Alice");`), the `optional` remains unchanged, and the output is still "Name: Alice". This behavior makes sense, but I'm confused about the implications of `emplace` in this context. Is there a better way to handle this situation? Should I reconsider how I'm using `std::optional`, or is there something fundamental I'm misunderstanding about its behavior with `emplace`? Any guidance would be appreciated! What am I doing wrong? I've been using Cpp for about a year now. This is for a desktop app running on Windows 10.