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AnkitKumarMishra5AnkitKumarMishra5
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JavaScript: Functions, Function scope
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‎JavaScript/Functions.html‎

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<!DOCTYPE html>
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<html lang="en">
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<head>
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<meta charset="UTF-8">
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<meta name="viewport" content="width=device-width, initial-scale=1.0">
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<title>Functions</title>
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</head>
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<body>
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<script>
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/*
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# Functions:
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- A set/block of code which is intended to peform a particular task
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- Function can be executed as many number of times as needed
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- Advantags of functions:
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- Avoid repeated code (redundancy)
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- DRY (Don't Repeat Yourself) principle
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- Modular code (Organized code)
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- For any function to be executed in JS, it needs two steps:
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- Declaration
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- Invokation (Calling the function)
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- Type of function:
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- Standard function
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- Anonymous function
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- Does not have a name
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- Used as a function expression
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- Syntax:
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- Declaration
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- STANDARD FUNCTION
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function name() {
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// code
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}
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- ANONYMOUS FUNCTION
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const name = function() {
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// code
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}
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- Invokation
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name()
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- Parameters and arguments:
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- Can make a function dynamic (For different I/P, you get different O/p)
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- Parameters: Function variables (Values expected by the function)
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- Arguments: Actual values passed for function paramaters during invokation
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- Syntax:
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- Declaration:
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function fun1(a, b) { // Parameters
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// code
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}
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- Invokation:
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func1(10, 20) // Arguments
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- 'return' keyword:
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- Return a value at the point where the function was invoked
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- Terminates the function execution at the point where return keyword was used
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*/
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/* --------------------------- */
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// function sayHi() {
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// console.log('START')
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// let num1 = 10
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// let num2 = 20
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// let sum = num1 + num2
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// console.log('Sum: ', sum)
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// console.log('END')
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// }
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// sayHi()
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// sayHi()
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// sayHi()
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/* --------------------------- */
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// function abc() {
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// console.log('ABC')
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// }
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// const abc = function () {
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// console.log('ABC')
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// }
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// abc()
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// abc()
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// abc()
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/* --------------------------- */
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/* # Example 1: Create a function to list the recipe steps for making a pizza
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1. Prepare the pizza base
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2. Add pizza sauce
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3. Add toppings
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4. Add cheeze
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5. Bake the pizza
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*/
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// function pizzaRecipe() {
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// console.log('1. Prepare the pizza base')
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// console.log('2. Add pizza sauce')
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// console.log('3. Add toppings')
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// console.log('4. Add cheeze')
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// console.log('5. Bake the pizza')
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// }
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// pizzaRecipe()
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// pizzaRecipe()
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// pizzaRecipe()
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/* --------------------------- */
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/* # Example 2: Create a function to find the sum of two numbers */
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// function sum(num1, num2) { // Parameters
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// console.log(num1 + num2)
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// }
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// sum(10, 20) // Arguments
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// sum(3784783984, 34709359)
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// sum(-15, 12)
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/* --------------------------- */
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/* # Example 3: Create a function to display the full name of the user if firstName and lastName are provided */
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// function printFullName(firstName, lastName) {
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// console.log(firstName + ' ' + lastName)
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// }
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// printFullName('Hayden', 'Thompson')
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// printFullName('Kelly', 'Cook')
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// printFullName('Happy', 'Singh')
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/* --------------------------- */
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/* # Example 4: Create a function which takes a number as parameter and logs whether it is an even number or odd number */
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// Way 1
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// function checkEvenOrOdd(num) {
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// if(num%2 == 0) {
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// console.log('Provided number is even')
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// } else {
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// console.log('Provdied number is odd')
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// }
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// }
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// Way 2
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// function checkEvenOrOdd(num) {
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// console.log(num % 2 ? 'Odd' : 'Even')
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// }
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// checkEvenOrOdd()
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/* --------------------------- */
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// function abc() {
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// console.log('START')
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// console.log('FUNCTIONS')
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// return
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// console.log('END')
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// }
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// abc()
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// function add(num1, num2) {
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// const sum = num1 + num2
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// return sum
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// }
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// const result = add(30, 50)
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// console.log(result)
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/* --------------------------- */
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/* # Example 5: Create a function which takes a number as parameter and checks whether it is an prime number or not */
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// function checkPrime(num1) {
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// for(let i = 2; i < num1; i++) {
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// if(num1 % i == 0) {
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// console.log('Provided number is not prime number')
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// return
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// }
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// }
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// console.log('Provided number is a prime number')
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// }
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// checkPrime(5)
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/* --------------------------- */
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/* # Example 6: Create a function which takes a number as parameter and returns the factorial of that number */
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// Way 1
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// function factorial(num) {
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// let fact = 1
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// for(let i = num; i >= 2; i--) { // 1
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// fact = fact * i // 120
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// }
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// return fact
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// }
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// Way 2
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// function factorial(num) {
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// let fact = 1
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// for(let i = 2; i <= num ; i++) { // 1
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// fact = fact * i // 120
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// }
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// return fact
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// }
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// console.log(factorial(6))
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/* --------------------------- */
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/* # Example 7: Create a function which takes a 2 numbers as parameters and returns the average of two numbers */
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// function getAverage(num1, num2) {
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// let avg = (num1 + num2) / 2
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// return avg
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// }
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// console.log(getAverage(11, 14))
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/* --------------------------- */
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/* # Example 8: Create a function which takes a 3 numbers as parameters and returns the greatest number (Assume that all 3 numbers are unequal) */
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// Way 1
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// function findMax(num1, num2, num3) {
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// if(num1 > num2 && num1 > num3) {
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// return num1
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// } else if (num2 > num1 && num2 > num3) {
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// return num2
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// } else {
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// return num3
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// }
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// }
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// Way 2
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// function findMax(num1, num2, num3) {
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// return Math.max(num1, num2, num3)
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// }
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// let result = findMax(25, 50, 75)
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// console.log(result + " is the greatest number")
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</script>
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</body>
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</html>

‎JavaScript/Scopes.html‎

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/*
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# Scope: Space where a variable can be accessed
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- Global scope: Variable can be accessed anywhere in the file
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- Function scope
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- Function scope: Variable can be accessed within the function
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- Block scope ({}): Variable can be accessed within the block
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# Declare variables
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// console.log(name + name)
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</script>
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</body>
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</html>
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<!--
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# Future:
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- Function scope
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-->
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</html>

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