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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.
The client, instead of writing code that invokes the "new" operator on a hard-coded class name, calls the clone() method on the prototype, calls a factory method with a parameter designating the particular concrete derived class desired, or invokes the clone() method through some mechanism provided by another design pattern.
In C++ computer programming, copy elision refers to a compiler optimization technique that eliminates unnecessary copying of objects.. The C++ language standard generally allows implementations to perform any optimization, provided the resulting program's observable behavior is the same as if, i.e. pretending, the program were executed exactly as mandated by the standard.
His book contains solutions to practical problems which C++ programmers may face. Several phrases from the book are now used within the C++ community as generic terms: modern C++ (as opposed to C/C++ style), policy-based design and typelist. [citation needed] All of the code described in the book is freely available in his library Loki. The ...
Copy-on-write (COW), also called implicit sharing [1] or shadowing, [2] is a resource-management technique [3] used in programming to manage shared data efficiently. Instead of copying data right away when multiple programs use it, the same data is shared between programs until one tries to modify it.