Closure

function z() {
  var b = 900;
  function x() {
    var a = 7;
    function y() {
      console.log(a, b);
    }
    y();
  }
  x();
}
z();

//This code defines three nested functions: z, x, and y. When z() is called, it sets the value of b to 900 and then calls x(). 
When x() is called, it sets the value of a to 7 and then calls y().
Finally, y() logs the values of a and b to the console, which are 7 and 900 respectively.
So, when you run z(), you should see the output 7 900 printed to the console.


CLOSURES IN JavaScript 


1. The inner function y() has access to the variables in the outer function x(), including a and b. 
This is an example of lexical scoping in JavaScript, which allows inner functions to access variables declared in outer functions.

2. The outer function x() has access to the variable b in the parent function z(). 
This is another example of lexical scoping and creates a closure over the variable b.

Closures occur when a function has access to variables in its outer (enclosing) scope, 
even after the outer function has returned. In this code, the function y() has access to a and b in its enclosing scopes, 
even though those variables were declared in separate functions.

In other words, the closure created by x() enables y() to "remember" the values of a and b from the time x() was called, 
even though x() has already completed execution.