What is the difference between scope and closure in programming languages?

What is the difference between scope and closure in programming languages?

Scope refers to the visibility of variables in different parts of your code, while closure is a function that retains access to its lexical scope even when the function is executed outside that scope.

Can you give me an example of closure in JavaScript?

Sure! In JavaScript, a closure is created when a function is defined inside another function. For example:

function outerFunction() {
    let outerVariable = 'I am outside!';
    function innerFunction() {
        console.log(outerVariable);
    }
    return innerFunction;
}

const myClosure = outerFunction();
myClosure(); // Outputs: I am outside!

How does closure work in Python?

In Python, closures work similarly. A nested function can access variables from its enclosing scope. Here's an example:

def outer_function():
    outer_variable = 'I am outside!'
    def inner_function():
        print(outer_variable)
    return inner_function

my_closure = outer_function()
my_closure()  # Outputs: I am outside!

Are there any languages where closures are not supported?

Yes, some older programming languages like C do not support closures natively. However, you can achieve similar behavior using function pointers and structures.