 This is known as Resource Acquisition Is Initialization (RAII), and ties resource management to object lifetime, ensuring that live objects have all necessary resources.Other approaches do not make holding the resource a class invariant, and thus objects may not have necessary resources (because they've not been acquired yet, have already been released, or are being managed externally), resulting in errors such as trying to read from a closed file.This approach ties resource management to memory management (specifically object management), so if there are no memory leaks (no object leaks), there are no resource leaks.