Homework6

let arr = [2, 5, 9, 15, 0, 4];

let result = [];

for(let i = 0; i < arr.length; i++) {
    if(arr[i] > 3 && arr[i]< 10) {
        result.push(arr[i])
    }
}
console.log(result);

//

let nums = [2, 0, 78, -21, 4, 88, -1, -81, 22];
let sum = 0;

for(let i of nums) {
    if(i > 0) {
        sum += i
    }
}
console.log(sum);

//

let arr = [1, 2, 5, 9, 4, 13, 4, 10];

for(let i of arr) {
    if(i === 4) {
        console.log('4 is here')
        break;
    }
}

//

let arr = [225, 12, 71, 32, 50, 9, 5, 41, 1, 13, 20];

for(let i of arr) {
    i = String(i)
    if(i.startsWith('1') || i.startsWith('2') || i.startsWith('5')) {
        console.log(+i)
    }
}

//

let nums = [1, 2, 3, 4, 5, 6, 7, 8, 9];
let str = '-';

for(let i = 1; i < nums.length + 1; i++) {
    str += i + '-'
}
console.log(str)

//

let week = ['mon', 'tue', 'wed', 'thu', 'fri', 'sat', 'sun'];
let day;
for(let i = 0; i < week.length; i++) {
    day = week[i]
    if (day === 'sat' || day === 'sun') {
        day = day.bold()
    }
    const p = document.createElement('p');
    p.innerHTML = day;
    document.body.appendChild(p)
}

//

let week = ['mon', 'tue', 'wed', 'thu', 'fri', 'sat', 'sun'];
let day = prompt('enter a day of week shortly');
for(let i = 0; i < week.length; i++) {
    if (week[i] === day) {
        week[i] = week[i].italics()
    }
    const p = document.createElement('p');
    p.innerHTML = week[i];
    document.body.appendChild(p)
}

//

let num = 1000;
let n = 0;
do{
    num /= 2
    n++
} while (num > 50);

console.log(n)
console.log(num)

//

function squareNum(n) {
    return Math.pow(n, 2)
}

console.log(squareNum(6))

//

function sum(x, y) {
    return x+y
}

console.log(sum(5, 10))

//

function calc(x, y, z) {
    return (x-y)/z
}

console.log(calc(50, 10, 2))

//

let n = prompt('enter a number of the day')

function showDay() {
    const week = ['понедельник', 'вторник', 'среда', 'четверг', 'пятница', 'суббота', 'воскресенье']
    for(let i = 0; i < week.length; i++) {
        if(+n === i+1) {
            return week[i]
        }
    }
}
console.log(showDay())

//

let sum = 0;
let array = [2.777, -0.335794, -1.524, 9.25, 76, 721.665, -83.2];
for(let item of array) {
    if(item < 0) {
        sum += item
    }
}
console.log(sum);

//

let num = prompt('enter a number');
num = +num;
let multiply = 1;
let arr = [];
for(let i = 0; i < num; i++) {
    arr.push(Math.random() * (999999 - -999999) + -999999);
    if(Math.abs(arr[i]) > 7) {
        multiply *= arr[i]
    }
}
console.log(multiply);

//

let num = prompt('enter a number');
num = +num;
let sum = 0;
let arr = [];
for(let i = 0; i < num; i++) {
    arr.push(Math.floor(Math.random() * 1000));
    if(arr[i] % 3 === 0) {
        sum += arr[i]
    }
}
console.log(sum);

//

let num = prompt('enter a number');
num = +num;
let arr = [];
let maxNum = 0;
let biggestNumIndex = 0;
for(let i = 0; i < num; i++) {
    arr.push(Math.floor(Math.random() * 1000));
    if(arr[i] > maxNum) {
        maxNum = arr[i]
    }
}
biggestNumIndex = arr.indexOf(maxNum)
console.log(biggestNumIndex);

//

let luckyNumbers = [];

function sum(x, y) {
    return Number(x) + Number(y)
}
function getLuckyNumbers() {
    for (let i = 1001; i < 10000; i++) {
        i = String(i)
        let num1 = i[0];
        let num2 = i[1];
        let num3 = i[2];
        let num4 = i[3];
        if (sum(num1, num2) === sum(num3, num4)) {
            luckyNumbers.push(+i);
        }
    }
    return luckyNumbers
}
console.log(getLuckyNumbers())