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In the C++ programming language, the assignment operator, =, is the operator used for assignment.Like most other operators in C++, it can be overloaded.. The copy assignment operator, often just called the "assignment operator", is a special case of assignment operator where the source (right-hand side) and destination (left-hand side) are of the same class type.
If a destructor is declared generation of a copy constructor is deprecated (C++11, proposal N3242 [2]). Move constructor if no copy constructor, copy assignment operator, move assignment operator and destructor are explicitly declared. Copy assignment operator if no move constructor and move assignment operator are explicitly declared.
Copy assignment operator – assign all the object's members from the corresponding members of the assignment operator's argument, calling the copy assignment operators of the object's class-type members, and doing a plain assignment of all non-class type (e.g. int or pointer) data members.
Other languages use different symbols for the two operators. [22] For example: In ALGOL and Pascal, the assignment operator is a colon and an equals sign (":=") while the equality operator is a single equals ("="). In C, the assignment operator is a single equals sign ("=") while the equality operator is a pair of equals signs ("==").
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).
All the operators (except typeof) listed exist in C++; the column "Included in C", states whether an operator is also present in C. Note that C does not support operator overloading. When not overloaded, for the operators && , || , and , (the comma operator ), there is a sequence point after the evaluation of the first operand.
The '=' (assignment) operator between two variables of the same structure type is overloaded by default to copy the entire content of the variables from one to another. It can be overwritten with something else, if necessary. Operators must be overloaded one by one, in other words, no overloading is associated with one another.
C++ also defines several global operators (such as operator new) that work on all classes, which the programmer can override. However, there is very little control over creating these defaults. Making a class inherently non-copyable, for example, may be done by declaring a private copy constructor and copy assignment operator and not defining them.