Explain the meaning of polymorphism describe how polymorphism is accomplished in C taking a suitable example?

Answer 1

Polymorphism in VC++ is the same as polymorphism in C++ itself. When you implicitly call a virtual method of a base class or one of its derivatives, then you rightly expect the most-derived override to execute instead, even when the runtime type is completely unknown to the caller and cannot be determined at runtime let alone compile time. You get that for free simply by overriding the known virtual methods of the base class, and without any need for expensive runtime type information, which is only useful if the caller is actually aware of the type in the first place, and which can only be predicted on a closed system. The whole point of polymorphism is that the base class (and therefore the caller) need know nothing whatsoever about any of its derivatives in order to execute more specialised methods. VC++ fully supports this aspect of OOP.

Answer 2

What is polymorphism? In programming languages, polymorphism means that some code or operations or objects behave differently in different contexts. For example, the + (plus) operator in C++: 4 + 5 <-- integer addition

3.14 + 2.0 <-- floating point addition

s1 + "bar" <-- string concatenation!

In C++, that type of polymorphism is called overloading.

Employee example: Here, we will represent 2 types of employees as classes in C++: * a generic employee (class Employee) * a manager (class Manager) For these employees, we'll store data, like their: * name * pay rate And...we'll require some functionality, like being able to: * initialize the employee * get the employee's fields * calculate the employee's pay To help demonstrate polymorphism in C++, we'll focus on the methods that calculate an employee's pay

# Employee class: Here is a class definition for a generic Employee: class Employee {

public:

Employee(string theName, float thePayRate);

string getName() const;

float getPayRate() const;

float pay(float hoursWorked) const;

protected:

string name;

float payRate;

};

Definitions for each of the methods follow: Employee::Employee(string theName, float thePayRate)

{

name = theName;

payRate = thePayRate;

}

string Employee::getName() const

{

return name;

}

float Employee::getPayRate() const

{

return payRate;

}

float Employee::pay(float hoursWorked) const

{

return hoursWorked * payRate;

}

Note that the payRate is used as an hourly wage. # Manager class: We'll also have a Manager class that is defined reusing the Employee class (i.e., via inheritance). Remember, if a manager inherits from an employee, then it will get all the data and functionality of an employee. We can then add any new data and methods needed for a manager and override (i.e., redefine) any methods that differ for a manager. Here is the class definition for a Manager: #include "employee.h"

class Manager : public Employee {

public:

Manager(string theName,

float thePayRate,

bool isSalaried);

bool getSalaried() const;

float pay(float hoursWorked) const;

protected:

bool salaried;

};

Definitions for the additional or overriddenmethods follow: Manager::Manager(string theName,

float thePayRate,

bool isSalaried)

: Employee(theName, thePayRate)

{

salaried = isSalaried;

}

bool Manager::getSalaried() const

{

return salaried;

}

float Manager::pay(float hoursWorked) const

{

if (salaried)

return payRate;

/* else */

return Employee::pay(hoursWorked);

}

The pay() method is given a new definition, in which the payRate has 2 possible uses. If the manager is salaried, payRate is the fixed rate for the pay period; otherwise, it represents an hourly rate, just like it does for a regular employee.

Answer 3

Polymorphism allows you to use derived objects generically. That is, it is not necessary to know the runtime type of an object in order to invoke specific behaviour. You get that for free via the virtual table.

For instance, suppose you design a generic shape class and from that you derive circle and square objects. The generic shape class has a draw method that is overridden by the derived classes. Thus it is not necessary for the calling code to know if the shape it holds is a generic shape or a specific shape. You simply call the generic draw method and the actual object (the runtime type) takes care of the specifics. In other words, you get polymorphic behaviour for free simply by calling virtual methods.

Since your calling code is generic, this makes it possible to cater for new objects (such as triangles), without the need to alter the calling code.

If you find yourself in the position where you have to determine the actual runtime type of an object then you should seriously consider redesigning your classes to make them more generic.

Answer 4

Polymorphism means "many forms", and it occurs when we have many classes that are related to each other by inheritance. To learn more about C Programming visit codeforhunger .com

Answer 5

c programming is structured programming