C++ LANGUAGE DATA ABSTRACTION EXAMPLES

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C++ LANGUAGE DATA ABSTRACTION EXAMPLES

Data Abstraction Example 



Any C++ program where you implement a class with public and 
private members is an example of data abstraction. Consider 
the following example: 

#include <iostream> 
using namespace std; 
 
class Adder{ 
   public: 
      // constructor 
      Adder(int i = 0) 
      { 
        total = i; 
      } 
      // interface to outside world 
      void addNum(int number) 
      { 
          total += number; 
      } 
      // interface to outside world 
      int getTotal() 
      { 
          return total; 
      }; 
   private: 
      // hidden data from outside world 
      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 compiled and 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 to know them to use the class. 
The private member total is something that the user doesn't need 
to know about, but is needed for the class to operate properly.