Interview :: C++
This pointer holds the address of the current object.
A scope resolution operator(::) is used to define the member function outside the class.
Delete [] is used to release the array of allocated memory which was allocated using new[] whereas delete is used to release one chunk of memory which was allocated using new.
The pure virtual function is a virtual function which does not contain any definition. The normal function is preceded with a keyword virtual. The pure virtual function ends with 0.
Syntax of a pure virtual function:
Let's understand this through an example:
Output:
javaTpoint
| Structures | class |
|---|---|
| A structure is a user-defined data type which contains variables of dissimilar data types. | The class is a user-defined data type which contains member variables and member functions. |
| The variables of a structure are stored in the stack memory. | The variables of a class are stored in the heap memory. |
| We cannot initialize the variables directly. | We can initialize the member variables directly. |
| If access specifier is not specified, then by default the access specifier of the variable is "public". | If access specifier is not specified, then by default the access specifier of a variable is "private". |
| The instance of a structure is a "structure variable". | |
Declaration of a structure: struct structure_name { // body of structure; } ; | Declaration of class: class class_name { // body of class; } |
| A structure is declared by using a struct keyword. | The class is declared by using a class keyword. |
| The structure does not support the inheritance. | The class supports the concept of inheritance. |
| The type of a structure is a value type. | The type of a class is a reference type. |
A class template is used to create a family of classes and functions. For example, we can create a template of an array class which will enable us to create an array of various types such as int, float, char, etc. Similarly, we can create a template for a function, suppose we have a function add(), then we can create multiple versions of add().
The syntax of a class template:
Syntax of a object of a template class:
Function overloading: Function overloading is defined as we can have more than one version of the same function. The versions of a function will have different signature means that they have a different set of parameters.
Operator overloading: Operator overloading is defined as the standard operator can be redefined so that it has a different meaning when applied to the instances of a class.
What is a virtual destructor?
A virtual destructor in C++ is used in the base class so that the derived class object can also be destroyed. A virtual destructor is declared by using the ~ tilde operator and then virtual keyword before the constructor.
Note: Constructor cannot be virtual, but destructor can be virtual.
Let's understand this through an example
- Example without using virtual destructor