recursion-and-loops.js

window.addEventListener('load', function() {

    // Recursion and loops (repetition)

    function greetings(str) {
        console.log(str)
        console.log(str)
        console.log(str)
    }

    greetings("hello everyone")

    function recursiveGreetings(str, count) {
        console.log(str)
        if (count > 1) {
            recursiveGreetings(str, count - 1)
        }
    }

    recursiveGreetings("Hello", 5)


    // While-Loop Version
    let count = 8
    let str = "Hello"
    while(count > 0) {
        console.log(str)
        count -= 1
    }

    // For-Loop Version
    let count = 4
    let str = "Welcome"
    for(let i = 0; i < count; i += 1) {
        console.log(str)
    }

    
    // Arrays
    let list = [2, 4, 4, 3, 4]
    for(let i = 0; i < list.length; i++) {
        list[i] = list[i] * 2
        console.log( list[i] )
    }

    // While Loop Version
    let fruits = ["Apple", "Banana", "Mango", "Lemon", "Strawberry"]
    let i = 0
    document.write('<ul>')
    while(i < fruits.length) {
        document.write('<li>' + fruits[i] + '</li>')
        i++
    }
    document.write('</ul>')

    
    // Find a number is an Array
    let numbers = [4, 99, 63, 77]
    let numberIndex = findNumber(numbers, 99)
    numbers[numberIndex] *= 100
    console.log(numbers)

    function findNumber(list, x) {
        let index = -1
        for(let i=0; i < list.length; i++) {
            if (list[i] === x) {
                index = i
                break;
            }
        }
        return index
    }

    // Loops are used when you have a collection of things
    // e.g., Database data are a collection.
    // quick-sort and merge-sort and some other algorithms are simpler recursivly
})