Задачи с циклами javascript

Источник

17 JavaScript for/while loop exercises with solutions

1. Write a JS code to print numbers from 1 to 10

Function `printNumbers()` prints numbers from 1 to 10 using for loop.

 > printNumbers() //1 2 3 4 5 6 7 8 9 10

2. Write a JS code to print a 2D array

Function `printArray()` prints all the elements of a 2D array using nested for loops.

 > > var arr = [[1, 2], [3, 4], [5, 6]]; printArray(arr) //1 2 3 4 5 6

3. Write a JS code to print Even numbers in given array

Function `printEven()` prints all the even numbers of a 2D array using for loops and ‘%’ operator.

 > > var arr = [13,23,12,45,22,48,66,100] printEven(arr) //12 22 48 66 100

4. Write a JS code to delete all occurrence of element in given array

Function `deleteElement()` deletes all the occurrence of element from the given array.

 > return arr; > var arr = [23,56,4,78,5,63,45,210,56]; arr = deleteElement(arr, 56) console.log(arr); //[23, 4, 78, 5, 63, 45, 210]

5. Write a JS code to demonstrate Async loop

For loop consisting of setTimeout() function to print loop variable 5 times in asynchronous way.

console.log(i), 5000);// 5 5 5 5 5 >

6. Write a JS code to find the power of a number using for loop

Function numPower() to returns power of number for provided exponential value using for loop.

 return res; > console.log(numPower(4,3)); //64 console.log(numPower(16,2)); //256

7. Write a JS code to print a pattern using for loop

Function printPattern() is used to print a pattern for a given range using nested for loop.

 console.log(str); > > printPatter(8); /* 1 1 2 1 2 3 1 2 3 4 1 2 3 4 5 1 2 3 4 5 6 1 2 3 4 5 6 7 1 2 3 4 5 6 7 8 */

8. Write a JS code to find the no of digits in a number

Function digitCount() to returns the number of digits in a given number using while loop.

 return count; > console.log(digitCount(8367)); //4 console.log(digitCount(563349)); //6

9. Write a JS code to calculate the sum of digits in a number

Function digitSum() to returns sum of all digits in a given number using while loop. Learn more about JavaScript built-in Math methods from developer.mozilla.org/Global_Objects/Math

 return sum; > console.log(digitSum(4367)); //20 console.log(digitSum(56349)); //27

10. Write a JS code to find the largest number in an array

Program to find the largest number in the given 1D array.

largest ? arr[i]:largest; //Check largest number > console.log(largest) //567

11. Write a JS code to find the number of zeros in 2D Matrix

Program to find count number for zeros in 2d matrix using nested for loops and increment operation.

12. Write a JS code to find product of two arrays

Function findProd() to generate a new array which is the product of two arrays of the same size using for loop.

arr2.length ? arr1 : arr2; for(var i=0; i < Math.min(arr1.length, arr2.length); i++)< arrProd[i] = arr1[i] * arr2[i]; //Product of 2 array elements >return arrProd; > var arr1 = [3,45,23,78,34]; var arr2 = [4,2,34,4,12,1]; console.log(findProd(arr1,arr2)); //[12, 90, 782, 312, 408, 1]

13. Write a JS code to print the Fibonacci series for a given value of N

The function fibonacci() prints the Fibonacci series for the given range N using While loop.

 > fibonacci(8) //0 1 1 2 3 5 8 13

14. Write a JS code to find N value in the Fibonacci series for a given number

The function Findfibonacci() prints the index of number in the Fibonacci series if present or “element not present” if the number is not part of the Fibonacci series.

 is present in index $`) break; > else if(n3>num) < console.log("Element not present"); break; >n1=n2; n2=n3; count++; > > findFibonacci(13) //"Element 13 is present in index 7" findFibonacci(144) //"Element 144 is present in index 12"

15. Write a JS code to count all letters in a word

Program to find the count of all letters in a word using double for loops.

 else < count[str.charCodeAt(i)-97]=1; // Add entry >> for(var i=0;i <26;i++)< if(count[i])< console.log(`Character $has occured $ number of times`); > >

16. Write a JS code to find duplicate values in a given array

Function findDup() to returns all the elements that are repeated more than once in a given array.

 > return arrDup; > var arr = [4,2,34,4,1,12,1,4]; console.log(findDup(arr)); //[4, 1]

17. Write a JS code for binary search algorithm

Program to find the index of a search element in an array using the binary search algorithm.

 else if(key > arr[mid]) < low=mid+1; >else if(key == arr[mid]) < flag++; console.log("found at index:"+mid); //print the position break; >> if(flag==0) < console.log("Not found"); // Element not present in array >

JavaScript Loop tutorials

Источник

Циклы JS

Подсчитать сумму всех чисел в заданном пользователем диапазоне.

let num1 = Number(prompt('Для подсчета суммы чисел в заданном диапазоне введите начальную цифру диапазона')); let num2 = Number(prompt('Введите конечную цифру')); let sum = 0; if (num1 < num2) < while (num1 ; > else if (num1 > num2) < while (num1 >= num2) < sum += num2; num2++; >; >; alert(`Сумма всех чисел в указанном диапазоне $`);

let number1 = Number(prompt('Для нахождения НОД двух чисел введите первую цифру')); let number2 = Number(prompt('Введите вторую цифру')); while (number1 != 0 && number2 != 0) < if (number1 >number2) < number1 = number1 % number2; >else < number2 = number2 % number1; >; >; alert(` Наибольший общий делитель двух указанных чисел равен $`);

let number = Number(prompt(' Введите число')); let divisor = []; for (let i = 2; i < number; i++) < if (number % i == 0 && number !== 1 ) < console.log(i); divisor.push(i); >; >; alert(`Все делители числа $: $`);

let userNumber = prompt(' Введите число'); let count = 0; for (let i = 0; i < userNumber.length; i++) < count += 1; >; alert(` Число состоит из $ цифр`);

let positive = 0; let negative = 0; let zero = 0; let even = 0; let odd = 0; for (let i = 1; i 0) < positive++; >; if (num < 0) < negative++; >; if (num == 0) < zero++; >; if (num % 2 == 0) < even++; >; if (num % 2 !== 0) < odd++; >; >; alert(` Из введенных цифр - положительных: $, отрицательных: $, нулей: $, четных: $, нечетных: $.`)

do < let firstNumber = prompt(' Введите первое число'); let secondNumber = prompt(' Введите второе число'); let operator = prompt(' Введите математический оператор', '+, -, *, /') let answer = eval(`$$ $`); alert(`Ответ $`); > while (confirm(' Решить еще один пример?'));

do < let q = prompt(' Введите число', '1234567890'); let move = Number( prompt(' На сколько цифр сдвинуть?') ); alert(q.slice(move) + q.slice(0, move)); >while (confirm(' Еще одно число ?'));

const days = ["понедельник", "вторник", "среда", "четверг", "пятница", "суббота", "воскресенье"]; let currentDay = 0; let nextDay; do < alert(`День недели - $.`); nextDay = confirm(' Хотите увидеть следующий день?'); currentDay++; if (currentDay === days.length) < currentDay = 0; >; > while (nextDay);

let tables = []; for (let i = 2; i :\n`); for (let j = 1; j * $ = $; `); >; >; alert(tables.join('')); console.log(tables.join(''));

let guessedNum = Number(alert("Загадайте число от 1 до 100")); let lowerLimit = 0; let upperLimit = 100; let N = 50; while (guessedNum !== N ) < let answer = prompt(`Ваше число >, `, '>, ') < lowerLimit = N; N = Math.ceil((upperLimit - lowerLimit) / 2 + lowerLimit); >else if (answer == ' <') < upperLimit = N; N = Math.ceil((upperLimit - lowerLimit) / 2 + lowerLimit); >else < break; >; >; alert(`Задуманное число $`);

Источник