Short notes on : 1. virtual function and pure virtual function. 2. class template 3. new and delete operators

 1. Virtual function and Pure Virtual function:

Virtual functions are functions declared in the base class that can be overridden in derived classes. When a virtual function is called on an object, the implementation of the function in the derived class is executed instead of the implementation in the base class. This is useful for implementing polymorphism and allowing derived classes to have different behavior for the same function. A pure virtual function is a virtual function that has no implementation in the base class and must be overridden in the derived class. A class with a pure virtual function is called an abstract class and cannot be instantiated.

2. Class Template:

A class template is a blueprint for creating a family of classes. It allows us to define a generic class that can work with different types of data. The class template is defined with one or more template parameters, which can be types, values, or other templates. When we create an object of a class template, we provide the actual types or values to be used in place of the template parameters. This allows us to reuse the same code with different data types and reduces code  duplication.

3. New and Delete Operators:

The 'new' operator is used to dynamically allocate memory for an object at runtime, while the 'delete' operator is used to deallocate memory previously allocated with the 'new' operator. When we use 'new' to allocate memory for an object, it returns a pointer to the memory block. We can then use this pointer to access the object and perform operations on it. When we are finished with the object, we must use the 'delete' operator to free the memory so that it can be used by the other parts of the program. Failing to free memory can lead to memory leaks and degrade performance. It is important to use 'new' and 'delete' carefully to avoid memory-related bugs and to follow best practices for memory management.