Athar Faridi

The statement outlines a fundamental difference in how Python and C# handle access modifiers for controlling the visibility and accessibility of class members. Python uses naming conventions (_ for protected, __ for private) to suggest encapsulation, but these are not strictly enforced, relying on developer discipline. C#, in contrast, enforces strict access control through explicit keywords like public, private, protected, and internal, which are checked at compile time. Below, I’ll elaborate on this difference in a pointwise manner with examples, followed by a difference table summarizing the key points.

Elaboration (Pointwise)

Access Modifier Mechanism:

Python: Uses naming conventions to indicate access levels. A single underscore _ suggests a protected member, and a double underscore __ triggers name mangling to simulate private access, but neither is strictly enforced.

Example:

class Person:
    def __init__(self, name, secret):
        self._name = name  # Protected by convention
        self.__secret = secret  # Pseudo-private via name mangling
    def get_secret(self):
        return self.__secret
 
p = Person("Alice", "hidden")
print(p._name)  # Outputs: Alice (accessible, though discouraged)
print(p._Person__secret)  # Outputs: hidden (accessible via mangling)

The _name and __secret are accessible, showing Python’s lack of strict enforcement.

C#: Uses explicit access modifier keywords (public, private, protected, internal, etc.) that are strictly enforced by the compiler.

Example:

public class Person {
    protected string name;
    private string secret;
    public Person(string name, string secret) {
        this.name = name;
        this.secret = secret;
    }
    public string GetSecret() {
        return secret;
    }
}
Person p = new Person("Alice", "hidden");
// Console.WriteLine(p.name);  // Compile-time error: inaccessible
// Console.WriteLine(p.secret);  // Compile-time error: inaccessible
Console.WriteLine(p.GetSecret());  // Outputs: hidden

Access to name and secret is strictly controlled by the compiler.

Protected Access:

Python: A single underscore _ indicates a protected member, but this is a convention, not a restriction. External code can still access it.

Example:

class Employee:
    def __init__(self, salary):
        self._salary = salary  # Protected by convention
    def show_salary(self):
        return self._salary
 
emp = Employee(50000)
print(emp._salary)  # Outputs: 50000 (accessible, though not recommended)

The _salary attribute is fully accessible outside the class.

C#: The protected keyword restricts access to the class and its derived classes, enforced at compile time.

Example:

public class Employee {
    protected decimal salary;
    public Employee(decimal salary) {
        this.salary = salary;
    }
    public decimal ShowSalary() {
        return salary;
    }
}
Employee emp = new Employee(50000);
// Console.WriteLine(emp.salary);  // Compile-time error: inaccessible
Console.WriteLine(emp.ShowSalary());  // Outputs: 50000

The salary field is only accessible within Employee or its subclasses.

Private Access:

Python: A double underscore __ triggers name mangling, renaming the member to _ClassName__member to discourage direct access, but it can still be accessed.

Example:

class BankAccount:
    def __init__(self, balance):
        self.__balance = balance  # Pseudo-private
    def get_balance(self):
        return self.__balance
 
account = BankAccount(1000)
print(account.get_balance())  # Outputs: 1000
print(account._BankAccount__balance)  # Outputs: 1000 (accessible via mangling)

Name mangling makes __balance harder to access accidentally but not impossible.

C#: The private keyword ensures the member is only accessible within the same class, with no external access possible.

Example:

public class BankAccount {
    private decimal balance;
    public BankAccount(decimal balance) {
        this.balance = balance;
    }
    public decimal GetBalance() {
        return balance;
    }
}
BankAccount account = new BankAccount(1000);
Console.WriteLine(account.GetBalance());  // Outputs: 1000
// Console.WriteLine(account.balance);  // Compile-time error: inaccessible

The balance field is completely inaccessible outside the class.

Default Access:

Python: Members without underscores are implicitly public, accessible from anywhere without restrictions.

Example:

class Student:
    def __init__(self, id):
        self.id = id  # Public by default
student = Student(123)
print(student.id)  # Outputs: 123

The id attribute is freely accessible.

C#: Members without an explicit access modifier default to private for fields and methods within a class, though classes themselves default to internal if no modifier is specified.

Example:

public class Student {
    int id;  // Implicitly private
    public Student(int id) {
        this.id = id;
    }
    public int GetId() {
        return id;
    }
}
Student student = new Student(123);
// Console.WriteLine(student.id);  // Compile-time error: inaccessible
Console.WriteLine(student.GetId());  // Outputs: 123

The id field is private by default, requiring a public method to access it.

Additional Modifiers in C#:

Python: Lacks additional access-related keywords beyond naming conventions, keeping the system simple but less controlled.
- Example:
```
class Team:
    def __init__(self, leader):
        self.leader = leader  # Public
        self._members = []  # Protected by convention
```
  Python relies on naming for all access control.

C#: Supports additional modifiers like internal (accessible within the same assembly) and protected internal (accessible within the same assembly or derived classes), offering finer-grained control.

Example:

public class Team {
    internal string leader;
    private List<string> members;
    public Team(string leader) {
        this.leader = leader;
        this.members = new List<string>();
    }
    public void AddMember(string member) {
        members.Add(member);
    }
}
Team team = new Team("Alice");
Console.WriteLine(team.leader);  // Accessible within same assembly
// Console.WriteLine(team.members);  // Compile-time error: inaccessible

C# provides more granular access control options.

Enforcement:

Python: Access control is not enforced by the language; it’s a convention that developers are expected to follow.

Example:

class Vault:
    def __init__(self, code):
        self.__code = code
vault = Vault("1234")
vault.__code = "9999"  # Creates new attribute, doesn’t affect __code
print(vault._Vault__code)  # Outputs: 1234 (original still accessible)

Name mangling doesn’t prevent access, and setting __code creates a new attribute.

C#: Access control is strictly enforced by the compiler, preventing unauthorized access at compile time.

Example:

public class Vault {
    private string code;
    public Vault(string code) {
        this.code = code;
    }
    public string GetCode() {
        return code;
    }
}
Vault vault = new Vault("1234");
// vault.code = "9999";  // Compile-time error: inaccessible
Console.WriteLine(vault.GetCode());  // Outputs: 1234

The compiler ensures code cannot be accessed or modified directly.

Inheritance and Access:

Python: Protected members (with _) are accessible in subclasses, and private members (with __) are mangled but still accessible with the correct name.

Example:

class Parent:
    def __init__(self):
        self._protected = "Protected"
        self.__private = "Private"
class Child(Parent):
    def show(self):
        return self._protected, self._Parent__private
child = Child()
print(child.show())  # Outputs: ('Protected', 'Private')

Both _protected and __private are accessible in the subclass.

C#: protected members are accessible in derived classes, but private members are not. This is strictly enforced.

Example:

public class Parent {
    protected string protectedField = "Protected";
    private string privateField = "Private";
    public (string, string) GetFields() {
        return (protectedField, privateField);
    }
}
public class Child : Parent {
    public string Show() {
        return protectedField;  // Accessible
        // return privateField;  // Compile-time error: inaccessible
    }
}
Child child = new Child();
Console.WriteLine(child.Show());  // Outputs: Protected

The compiler restricts access to privateField in the derived class.

Difference Table

Aspect	Python	C#
Access Modifiers	Naming conventions: `_` (protected), `__` (private) (e.g., `self.__secret`)	Explicit: `public`, `private`, `protected`, `internal` (e.g., `private string secret;`)
Protected Access	`_` convention, accessible (e.g., `p._name`)	`protected`, restricted to class and subclasses (e.g., `protected string name;`)
Private Access	`__` with name mangling, accessible via `_ClassName__member`	`private`, strictly inaccessible outside class (e.g., `private string secret;`)
Default Access	Public by default (e.g., `self.id`)	`private` for members, `internal` for classes (e.g., `int id;`)
Additional Modifiers	None, only naming conventions	`internal`, `protected internal`, etc. (e.g., `internal string leader;`)
Enforcement	Not enforced, relies on convention (e.g., `p._Person__secret`)	Strictly enforced at compile time (e.g., `p.secret` causes error)
Inheritance Access	`_` and `__` accessible in subclasses with mangling (e.g., `_Parent__private`)	`protected` accessible, `private` inaccessible in subclasses
Example	`self._name = name; self.__secret = "hidden"`	`protected string name; private string secret = "hidden";`

This detailed comparison and table clarify the differences in access modifiers between Python and C#, with examples illustrating their practical implications.

Class Declaration Indentation And Braces