What is the difference between Public, Static, void?

1. **Public**:

   - `Public` is an access modifier in programming languages like Java or C#. It means that a method or variable can be accessed from anywhere in the program. It's like leaving the door open for anyone to use.

2. **Static**:

   - `Static` is a keyword that means something belongs to the class itself, not to instances of the class. It's like a shared resource that all instances of the class can access. You don't need an object to use it.

3. **void**:

   - `void` is a keyword used in method declarations to indicate that the method doesn't return anything. It's like a promise that the method will do something, but it won't give you anything back.

**Example** (in Java or C# ):

public class Example {

    public static void greet() {

        System.out.println("Hello, world!"); // Printing a greeting

    }

    public static void main(String[] args) {

        greet(); // Calling the greet method

    }

}

Explanation:

- `public`: This means that the `greet` method can be accessed from anywhere in the program.

- `static`: This means that the `greet` method belongs to the class itself, not to any particular instance of the class.

- `void`: This means that the `greet` method doesn't return anything. It just prints "Hello, world!" to the console when it's called.

So, when we call `greet()` in the `main` method, it prints "Hello, world!" to the console, but it doesn't return any value.

What is hoisting in JavaScript?

**Hoisting in JavaScript**:

Hoisting is like when you magically lift things up. In JavaScript, it means that declarations (like variables and functions) are lifted or brought to the top of their scope during the code execution. 

**Example**:

console.log(x); // Output: undefined

var x = 10;

Explanation:

Even though we're trying to `console.log(x)` before declaring `x`, JavaScript doesn't give an error. Instead, it "hoists" the declaration of `x` to the top, which means it's like saying `var x;` is moved to the very top of the scope:

var x;

console.log(x); // Output: undefined

x = 10;

So, when we `console.log(x)` before assigning `x` a value, it outputs `undefined` because `x` exists (it's been declared), but it hasn't been assigned a value yet.

What is the difference between let and var in JavaScript?

**Scope:**

   - `let`: Variables declared with `let` are limited to the block they are declared in. They are only accessible within the block of code where they are defined.

   - `var`: Variables declared with `var` are function-scoped or globally scoped. They are accessible throughout the entire function where they are defined, or globally if not within a function.

// Using let

function letExample() {

    let x = 10;

    if (true) {

        let y = 20;

        console.log(x); // Output: 10

        console.log(y); // Output: 20

    }

    console.log(x); // Output: 10

    console.log(y); // ReferenceError: y is not defined

}

letExample();

// Using var

function varExample() {

    var x = 10;

    if (true) {

        var y = 20;

        console.log(x); // Output: 10

        console.log(y); // Output: 20

    }

    console.log(x); // Output: 10

    console.log(y); // Output: 20 (accessible due to var's function scope)

}

varExample();

In the `letExample`, `x` is accessible within the function `letExample`, but `y` is only accessible within the `if` block where it's defined. Trying to access `y` outside the `if` block will result in a `ReferenceError`.

In the `varExample`, both `x` and `y` are accessible within the entire `varExample` function, even though `y` is defined inside the `if` block. This is because variables declared with `var` are function-scoped.