Containership Vs. Inheritance

Containership is the concept of having one or more objects of one or more classes as data members of another class. Containership is the capacity of a class to contain objects of different classes as member’s data. For example, the class A could contain an object of class B as a member. Here, all public functions defined in B can be used in the class A. The Class A becomes the container, while the class B becomes the contained class. In OOP, Containership represents one ‘has – a’ relation. It is important to note that, although the container has access to carry out all public methods of the contained class, it is not able to change or provide additional functionality.

Inheritance is the capacity for a class to inherit properties and behavior of a parental class by spreading it. Inheritance principally provides code reuse by allowing extending properties and behavior of an existing class by a newly defined class. If the class A is created from Class B, therefore the class B is parent class and the class A is called the child class (or derived class/sub class). The behavior of parent class can be overridden by derived class i.e. a derive class can modify the functions of parent class in it.

Difference between Containership and Inheritance:

If a class is extended, it inherits all public and protected properties/ behaviours and these behaviours can be overridden by the subclass. But if a class is contained in other one, the container does not get the capacity to change or add behavior to the contained class i.e. container. In Inheritance, the behavior of parent class can be overridden by derived class i.e. a derive class can modify the functions of parent class in it.

Inheritance represents ‘is -a ‘relationship in OOP, while Containership represents a’ has -a’ relationship.

Exceptions/ Exception Handling in C++

An exception is a problem that arises during the execution of a program. A C++ exception is a response to an exceptional circumstance that arises while a program is running, such as an attempt to divide by zero or infinite loop etc.

Exceptions provide a way to transfer control from one part of a program to another. C++ exception handling is built upon three keywords: try, catch, and throw.

•     throw: A program throws an exception when a problem shows up. This is done using a throw keyword.
•      catch: A proram catches an exception with an exception handler at the place in a program where you want to handle the problem. The catch keyword indicates the catching of an exception.
•      try: A try block identifies a block of code for which particular exceptions will be activated. It's followed by one or more catch blocks.

Assuming a block will raise and exception, a method catches an exception using a combination of the try and catch keywords. A try/catch block is placed around the code that might generate an exception. Code within a try/catch block is referred to as protected code, and the syntax for using try/catch looks like the following:

ALGORITHM:

Step 1: Start the program.

Step 2: Declare the variables a,b,c.

Step 3: Read the values a,b,c,.

Step 4: Inside the try block check the condition.

            a. if(a-b!=0) then calculate the value of d and display.

            b. otherwise throw the exception.

Step 5: Catch the exception and display the appropriate message.

Step 6: Stop the program.

PROGRAM:

#include

#include

void main()

{

   int a,b,c;

   float  d;

   clrscr();

   cout<<"Enter the value of a:";

   cin>>a;

   cout<<"Enter the value of b:";

   cin>>b;

   cout<<"Enter the value of c:";

   cin>>c;

   

   try

   {

              If ((a-b) != 0)

              {

                 d=c/(a-b);

                 cout<<"Result is:"<

              }

              else

              {

                 throw(a-b);

              }

   }

   Catch (int i)

   {

              cout<<"Answer is infinite because a-b is:"<

   }

     getch();

}

Output:

              Enter the value for a: 20

              Enter the value for b: 20

              Enter the value for c: 40

             Answer is infinite because a-b is: 0