Properties

Definition :

A property is a class member that provides a flexible mechanism to read, write, or compute the value of a private field. Properties encapsulate private data while exposing controlled access through getters and setters.

Properties help implement encapsulation by allowing controlled access to internal data.

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C++

Note: C++ does not have built-in properties like C# or some other languages. Instead, getter and setter methods are used to control access to private data members, simulating properties.

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Syntax (Using Getter and Setter methods)**

class ClassName {
private:
    int data;

public:
    // Setter
    void setData(int value) {
        data = value;
    }

    // Getter
    int getData() {
        return data;
    }
};

Example

#include <iostream>
using namespace std;

class Account {
private:
    double balance;

public:
    // Setter method (simulating a property)
    void setBalance(double amount) {
        if (amount >= 0)
            balance = amount;
        else
            cout << "Invalid balance amount." << endl;
    }

    // Getter method
    double getBalance() {
        return balance;
    }
};

int main() {
    Account acc;
    acc.setBalance(1000.50);
    cout << "Balance: " << acc.getBalance() << endl;

    acc.setBalance(-500);  // Invalid

    return 0;
}

C#

Syntax(Uses built-in get/set keywords)

class className {
    private string name;

    public string Name {
        get { return name; }
        set { name = value; }
    }
}

Example

class Person {
    private string name;

    public string Name {
        get { return name; }
        set { name = value; }
    }

    public void displayName() {
        Console.WriteLine("Name: " + Name);
    }
}

class Program {
    static void Main() {
        Person p = new Person();
        p.Name = "Alice";            // using property setter
        p.displayName();             // using property getter inside method
    }
}

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Java

Syntax(Uses explicit getter/setter methods)

class className {
    private String name;

    public String getName() {
        return name;
    }

    public void setName(String value) {
        name = value;
    }
}

Example

public class Person {
    private String name;

    public String getName() {       // getter
        return name;
    }

    public void setName(String name) { // setter
        this.name = name;
    }

    public void displayName() {
        System.out.println("Name: " + getName());
    }

    public static void main(String[] args) {
        Person p = new Person();
        p.setName("Alice");         // using setter
        p.displayName();            // using getter inside method
    }
}

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Python

Syntax(Uses @property decorator)

class className:
    def __init__(self):
        self._name = ""

    @property
    def name(self):
        return self._name

    @name.setter
    def name(self, value):
        self._name = value

Example

class Person:
    def __init__(self):
        self._name = ""

    @property
    def name(self):                # getter
        return self._name

    @name.setter
    def name(self, value):        # setter
        self._name = value

    def display_name(self):
        print("Name:", self.name)

p = Person()
p.name = "Alice"                   # using setter
p.display_name()                  # using getter

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JavaScript

Syntax(Uses get/set in class definition)

class className {
    constructor() {
        this._name = "";
    }

    get name() {
        return this._name;
    }

    set name(value) {
        this._name = value;
    }
}

Example

class Person {
    constructor() {
        this._name = "";
    }

    get name() {                  // getter
        return this._name;
    }

    set name(value) {             // setter
        this._name = value;
    }

    displayName() {
        console.log("Name:", this.name); // using getter
    }
}

const p = new Person();
p.name = "Alice";                 // using setter
p.displayName();                  // using getter

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TypeScript

Note: TypeScript supports getter and setter methods using the get and set keywords, which allow safe and controlled access to class properties—similar to C# and more elegant than C++.

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Syntax (Using Getter and Setter methods)

class ClassName {
    private _data: number;

    // Setter
    set data(value: number) {
        this._data = value;
    }

    // Getter
    get data(): number {
        return this._data;
    }
}

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Example

class Account {
    private _balance: number = 0;

    // Setter method (simulating a property)
    set balance(amount: number) {
        if (amount >= 0) {
            this._balance = amount;
        } else {
            console.log("Invalid balance amount.");
        }
    }

    // Getter method
    get balance(): number {
        return this._balance;
    }
}

const acc = new Account();
acc.balance = 1000.50;  // Setter called
console.log("Balance: " + acc.balance);  // Getter called

acc.balance = -500;  // Invalid

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