Classes and Object

Class and Object:


Defining the Class

Here’s the definition (sometimes called a specifier) for the class syllabusme,
examples:
class syllabusme //define a class
{
private:
int somedata; //class data
public:
void setdata(int d) //member function to set data
{ somedata = d; }
void showdata() //member function to display data
{ cout << “\nData is “ << somedata; } };
The definition starts with the keyword class, followed by the class name—smallobj in this example. Like a structure, the body of the class is delimited by braces and terminated by a semicolon. (Don’t forget the semicolon. Remember, data constructs such as structures and classes end with a semicolon, while control constructs such as functions and loops do not.)

private and public:
The body of the class contains two unfamiliar keywords: private and public. What is their purpose?
A key feature of object-oriented programming is data hiding. This term does not refer to the activities of particularly paranoid programmers; rather it means that data is concealed within a class so that it cannot be accessed mistakenly by functions outside the class. The primary mechanism for hiding data is to put it in a class and make it private. Private data or functions can only be accessed from within the class. Public data or functions, on the other hand, are accessible from outside the class.