IS IT POSSIBLE TO DEFINE THE FUNCTION IN ANOTHER FUNCTION:
==========================================================

// Nested Functions

let square = function(x) // outer function
{
    var s = x * x;

    let cube = function(x) // inner function
    {
        var c =  s * x;

        console.log("The Cube = "+c);
    }
    cube(x);
    return s;
}

result = square(8);
console.log("The Square = "+result);
// cube(7);

=======================================================

9876 = 9+8+7+6
==============
f1()
{
	f2()
	{
		get individual digits
	}
	sum_of_digits
}

==============================

let sum_digits = function(num)
{
    let ind_digits = function()
    {
        i = num;
        while(i != 0)
        {
            rem = i % 10;
        }
        return rem;
    }
    let s = 0;
    s += ind_digits();
    i = Math.floor(i / 10);
    console.log("The sum = "+s);
}
sum_digits(876543);
=========================================
Callback Function:
==================
Sending a function as an argument to another function is called as "callback function".
==> the function can be perform the operation after the another function.

Syntax:
function fun1(f2)
{
	implementation
}
function f2()
{
	implementation
}

fun1(f2)

setTimeout():
============

function f1(f2)
{
    console.log("Hi");
    console.log("Hello");
    setTimeout(function(){
        f2(),1000
        })
}
function f2(result)
{
    console.log("Welcome to Ashok IT.");
}

f1(f2);
================================
currying:
=========
f1(x,y,z)
{
	return x * y * Z;
}

f1(x)
{
	return function(y)
	{
		return function(z)
		{
			return x * y * z;
		}
	}
}

function volume(length)
{
    return function(breadth)
    {
        return function(height)
        {
            return length * breadth * height;
        }         
    }
}

console.log("The Volume = "+volume(4)(5)(6));