Hiding Complex Implementation in C++
Hiding a user-defined complex class implementation is an essential and important programming feature or concept in the C++ programming language (OOPS). It enhances the concept of encapsulation within a root or base class and the subclass abstraction concept of multiple derived classes within a class. This feature allows C++ users to directly interact with the system using a simple class interface without knowing the internal complexity. This is often referred to as the “black box” principal concept in C++, where the implementation details of a class are hidden, and only essential details are exposed when needed.
The concept of hiding class implementations is implemented using several mechanisms in C++.
- Encapsulation – Encapsulation features include hiding data types within existing class objects and providing access to their data members through class methods.
- Abstraction – Providing only the essential class interface (which defines public class methods) and hiding the class implementation details (which defines essential private class methods and data type members) from the general user.
- Pimpl Idiom (Pointer to Implementation) – Hiding implementation details in an existing class is a common C++ programming technique or concept for improving class program source code compilation time and reducing coupling between C++ program header and source code files.
- Private and Protected Access Specifiers – Blocking access to class data type parameter variable data members by using access control keywords (private, protected, public) in the existing class data member access method.
A special concept for hiding complex implementations in C++ programming.
Encapsulation concept in C++.
Encapsulation in C++ programs is a technique or concept that bundles user-defined class data type members and custom class methods that operate on that data into a single unit or class.
This helps hide the internal processes of any user-defined custom class from the outside world, exposing essential class functionality only through user-defined public class methods.
Abstraction concept in C++.
The abstraction concept in C++ programs focuses on providing a clear and easy interface for directly interacting with a user-defined class object, while keeping the class’s implementation details hidden.
Using abstraction methods in an existing class ensures that the class user only knows what the multiple individual class objects defined within the existing class do, not how they perform these tasks.
Class data members concept of access control (public, private, protected) in C++.
- Public – Public class data members defined and declared within a class can be called, accessed, and directly managed from anywhere in the base or subclasses.
- Private – User-defined class data type parameter members can only be accessed and managed from within the same class. This is an important tool used to hide implementation details within a class.
- Protected – Protected class data variable members can only be accessed and managed from within the class and derived classes.
The concept of hiding a complex implementation using the encapsulation method in C++.
So, let’s create a simple example of a UserAccount class in C++ programming. In this, we will hide the internal user account deposit balance and the logic for modifying it, and display it with only a simple interface for depositing and withdrawing money from the user account.
Example of hiding a complex implementation using the encapsulation concept.
#include <iostream>
#include <string>
using namespace std;
class UserAccount {
private:
double Acbalance; // here we define a private class member to hide the internal variable state
// here we create Private isValidAmount function to validate the amount
bool isValidAmount(double dpMoney) {
return dpMoney > 0;
}
Public:
// here we create class Constructor method
UserAccount(double initial_Acbalance) : Acbalance(initial_Acbalance) {}
// here we define class Public methods to interact with the Account balance class members
void deposit(double dpMoney) {
if (isValidAmount(dpMoney)) {
Acbalance += dpMoney;
cout << “Deposited Amount is – ” << dpMoney << endl;
} else {
cout << “Invalid account deposit amount is -” << endl;
}
}
void withdraw(double dpMoney) {
if (isValidAmount(dpMoney) && Acbalance >= dpMoney) {
Acbalance -= dpMoney;
cout << “Withdrawal account amount is – ” << dpMoney << endl;
} else {
cout << “Insufficient withdrawal Account balance amount is -” << endl;
}
}
double previewBalance() const {
return Acbalance;
}
};
int main() {
UserAccount account(10000.0); // here we Create class account member with an initial balance
cout << “Initial account balance – Rs-” << account.previewBalance() << endl;
account.deposit(1340.0); // this is work for deposit account money
cout << “Updates account balance is – Rs-” << account.previewBalance() << endl;
account.withdraw(389.0); // this is work for Withdraw account money
cout << “Updated balance is – Rs-” << account.previewBalance() << endl;
account.withdraw(2387.0); // this is work for Try to use invalid account amount withdrawal
cout << “Final account balance is – Rs-” << account.previewBalance() << endl;
return 0;
}
Explanation of hiding a complex implementation using encapsulation.
- In this example, the UserAccount class defines a private data member called balance, which cannot be directly accessed from outside the UserAccount class. This strictly blocks any modifications to the user account balance due to errors.
- The class method isValidAmount() is a private function defined in UserAccount. This class method is used to internally check the amount deposited and withdrawn from the UserAccount to validate it. This is hidden from the user, and they can only interact with the public methods deposit() and withdrawal() defined in the class.
- The public methods deposit(), withdrawal(), and previewBalance() defined in the class allow controlled access to the balance. In which a typical user does not need to know how the balance is stored in their account, or how the internal logic for deposits and withdrawals in an existing UserAccount works.
Advantages of hiding a complex class implementation in a C++ program.
- Control – In the UserAccount class, we can control how the internal account data (balance) defined in the class is modified, allowing us to only perform these operations through the correct class.
- Flexibility – In the UserAccount class, we can modify the default implementation of function methods like Deposit(), Withdrawal(), or how the balance is stored, without directly impacting the source code that uses the UserAccount class.
- Security – In which the UserAccount user cannot directly access or modify any balance. This helps in avoiding any mistaken usage or other mistakes in the User Account.
