Copy constructor in c example pdf documentation

A copy constructor to make a copy of the dynamically allocated memory. Copy an object to pass it as an argument to a function. Constructors enable the programmer to set default values, limit instantiation, and write code that is flexible and easy to read. Normal constructor allocating ptr copy constructor allocating ptr. The class defines two constructors and one destructor. Copy constructor is called when a new object is created from an existing object, as a copy of the existing object. For union types, the implicitlydefined copy constructor copies the object representation as by stdmemmove.

For example, as already noted earlier, if you do not declare a copy constructor, the. Copy constructor uses to initialize an object using another object of the same class. In the above example 1 calls copy constructor and 2 calls assignment operator. This means it copies all the data from the object you are assigning it to, without actually initializing the object that is being copied onto.

In the previous example you can see when c1 called concatenate, changes happens in both c1 and c2, because both are pointing to same memory location. For nonunion class types class and struct, the constructor performs full memberwise copy of the objects bases and nonstatic members, in their initialization order, using direct initialization. Assignment operator is called when an already initialized object is assigned a new value from another existing object. The compilergenerated copy constructor simply copies the pointer, so that the new pointer still points to the others memory location. Copy constructor on the other hand, is the complete opposite of the assignment constructor. A copy constructor is the member function which initializes an object using another object of the same class. And, it creates a new object, which is exact copy of the existing copy, hence it is called copy constructor. For example, if a class member is a pointer then you need to define a copy constructor to allocate new memory and copy the values from the others pointedto object. Here is an example of objects being created in main using. Initialize one object from another of the same type. A class or struct may have multiple constructors that take different arguments. In the below example you can see user defined copy constructor i. The copy constructor is a constructor which creates an object by initializing it with an object of the same class, which has been created previously.