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In VBA, an assignment of variables of type Object is a shallow copy, an assignment for all other types (numeric types, String, user defined types, arrays) is a deep copy. So the keyword Set for an assignment signals a shallow copy and the (optional) keyword Let signals a deep copy. There is no built-in method for deep copies of Objects in VBA.
C++ objects in general behave like primitive types, so to copy a C++ object one could use the '=' (assignment) operator. There is a default assignment operator provided for all classes, but its effect may be altered through the use of operator overloading. There are dangers when using this technique (see slicing).
If the default behavior ("shallow copy") is actually the intended one, then an explicit definition, although redundant, will be "self-documenting code" indicating that it was an intention rather than an oversight. Modern C++ includes a syntax for expressly specifying that a default function is desired without having to type out the function body.
Array's destructor deletes the data array of the original, therefore, when it deleted copy's data, because they share the same pointer, it also deleted first's data. Line (2) now accesses invalid data and writes to it. This produces a segmentation fault. If we write our own copy constructor that performs a deep copy then this problem goes away.
Shallow copy, in contrast to deep copy; Single responsibility principle; Singleton pattern; Singly rooted hierarchy; Slicing; Specification class, a class implementing abstract class; Stack-based memory allocation; Static method; Static typing, in contrast to dynamic typing; Strong and weak typing; Subclass (also called child class or derived ...
Making a shallow copy of a const or immutable value removes the outer layer of immutability: Copying an immutable string (immutable(char[])) returns a string (immutable(char)[]). The immutable pointer and length are being copied and the copies are mutable. The referred data has not been copied and keeps its qualifier, in the example immutable.
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Copy and paste is a less formal alternative to classical branching, often used when it is foreseen that the branches will diverge more and more over time, as when a new product is being spun off from an existing product. As a way of spinning-off a new product, copy-and-paste programming has some advantages.