c++ Is there still a need to provide default constructors to use STL containers

Yes, if a class lacks a default constructor and is used in certain contexts within the STL, such as creating instances in containers or resizing containers, it may lead to compilation errors. When a container needs to create objects of a type, it relies on the availability of a default constructor for that type. If the class does not provide a default constructor, these operations cannot be performed, resulting in compilation errors. To resolve this, either provide a default constructor for the class or choose appropriate alternatives to handle the instantiation requirements of the STL containers.