Organizing C Class Members in C : A Comprehensive Guide

When working with C classes, it's crucial to organize your code in a way that makes it easily readable and maintainable. Proper organization helps in reducing the complexity of the code and enhances understanding. In this guide, we'll explore a structured way of organizing class members, including constructors, destructors, data members, and member functions. This is also beneficial when creating header files (like account.h) and implementing the corresponding methods in the source files (like account.cpp).

Class Organization by Access Specifiers

Firstly, class members are organized by access specifiers: public, protected, and private. At the top level, each section starts with the correct access specifier. Within each of these sections, the members are organized as follows:

Access Specifiers Order

1. Public members

2. Protected members

3. Private members

Details of Members Within Access Specifiers Section

Once the access specifiers have been defined, the members are organized as follows:

Constructor, Destructor, and Data Members First

Within each access specifier section, constructors and destructors come first, followed by data members (variables), and finally by member functions (methods). If there are any typedefs or constants, they are listed before the constructors.

Example: BankAccount Class

Let's consider the BankAccount class to understand this better.

account.h:

#ifndef _BANK_ACCOUNT_H_
#define _BANK_ACCOUNT_H_
class BankAccount {
public:
  BankAccount();
  BankAccount(double initial_balance);
  void deposit(double amount);
  void withdraw(double amount);
  void add_interest(double rate);
  double get_balance() const;
private:
  double balance;
};
#endif

account.cpp:

#include "account.h"
BankAccount::BankAccount() {
  this->balance  0;
}
BankAccount::BankAccount(double initial_balance) {
  this->balance  initial_balance;
}
void BankAccount::deposit(double amount) {
  this->balance   amount;
}
void BankAccount::withdraw(double amount) {
  this->balance - amount;
}
void BankAccount::add_interest(double rate) {
  this->balance   this->balance * rate;
}
double BankAccount::get_balance() const {
  return this->balance;
}

In the above code, the class members are organized as follows within the public section:

BankAccount(); - Constructor BankAccount(double initial_balance); - Constructor with parameter void deposit(double amount); - Member function void withdraw(double amount); - Member function void add_interest(double rate); - Member function double get_balance() const; - Member function (const method)

Static vs Non-Static Methods

Within the method groups, it's also a good practice to separate static methods from non-static methods. This is particularly useful as it differentiates between methods that operate on the class in a static context and those that operate on an instance of the class.

Example Code Explanation

Let's break down the example code provided:

test.cpp:

#include iostream
using namespace std;
int main() {
  BankAccount harry's_account(1000);
  harry's_(500); // Balance is now 1500
  harry's_account.withdraw(2000); // Balance is now 1490
  harry's__interest(0.149); // Balance is now 1490   14.90  1490.90
  cout  fixed  setprecision(2)  harry's__balance()  endl;
  return 0;
}

Here's a line-by-line explanation of the code:

#include iostream - Includes the standard stream library for input and output operations. using namespace std; - Uses the standard namespace to avoid prefixing standard library items with std::. int main() { ... } - The main function, where the program begins execution. BankAccount harry's_account(1000); - Creates an instance of BankAccount with an initial balance of 1000. harry's_(500); - Adds 500 to the current balance. harry's_account.withdraw(2000); - Deducts 2000 from the current balance. Note: Assuming the balance is less than 2000, it should result in a negative balance. harry's__interest(0.149); - Adds 14.9% interest to the current balance. cout fixed setprecision(2) harry's__balance() endl; - Prints the current balance with fixed point notation and 2 decimal places. return 0; - Indicates successful execution of the program.

This organization style not only enhances readability but also adheres to a common convention in C programming. Proper organization of class members is a fundamental aspect of writing maintainable and efficient C code.