All c++ programs are composed of the following two fundamental elements
- Program statements(code)-This is the part of a program that performs actions and they are called functions
- Program data-The data is the information of the program which gets affected by the program functions
Encapsulation is an Object Oriented Programming concept that binds together the data and functions that manipulate the data,and keeps both safe from outside interference and misuse,Data encapsulation led to the important OOP concept of data hiding
Data encapsulation is a mechanism of bundling the data,and the functions that use them and data abstraction is a mechanism of exposing only the interfaces and hiding the implementation details from the user.
C++ supports the properties of encapsulation and data hiding through the creation of user-defined types,called classes.The class contain private ,protected and public members.By default all items defined in a class are private
Any C++ program where you implement a class with public and private members is an example of data encapsualation and data abstraction
eg:
#include<iostream.h>
class Adder {
public:
Adder(int i=0) {
total = i;
}
void addNum(int number) {
total+=number;
}
int getTotal() {
return total;
};
private:
int total;
};
int main() {
Adder a;
a.addNum(10);
a.addNum(20);
a.addNum(30);
cout<<"total" <<a.getTotal() <<endl;
return 0;
}
When the above code is executed ,it produces the following result
Total 60
- Above class adds numbers together ,and returns the sum
- The public members addNum and getTotal are the interfaces to the outside world and a user needs them to use the class
- The private member total is something that is hidden from the outside world
- but is needed for class to operate properly
