freecodecamp--freecodecamp/curriculum/challenges/english/blocks/daily-coding-challenges-javascript/6821ebdf237de8297eaee793.md

id, title, challengeType, dashedName

id	title	challengeType	dashedName
6821ebdf237de8297eaee793	Challenge 17: Unorder of Operations	28	challenge-17

--description--

Given an array of integers and an array of string operators, apply the operations to the numbers sequentially from left-to-right. Repeat the operations as needed until all numbers are used. Return the final result.

For example, given [1, 2, 3, 4, 5] and ['+', '*'], return the result of evaluating 1 + 2 * 3 + 4 * 5 from left-to-right ignoring standard order of operations.

• Valid operators are +, -, *, /, and %.

--hints--

evaluate([5, 6, 7, 8, 9], ['+', '-']) should return 3

assert.equal(evaluate([5, 6, 7, 8, 9], ['+', '-']), 3);

evaluate([17, 61, 40, 24, 38, 14], ['+', '%']) should return 38

assert.equal(evaluate([17, 61, 40, 24, 38, 14], ['+', '%']), 38);

evaluate([20, 2, 4, 24, 12, 3], ['*', '/']) should return 60

assert.equal(evaluate([20, 2, 4, 24, 12, 3], ['*', '/']), 60);

evaluate([11, 4, 10, 17, 2], ['*', '*', '%']) should return 30

assert.equal(evaluate([11, 4, 10, 17, 2], ['*', '*', '%']), 30);

evaluate([33, 11, 29, 13], ['/', '-']) should return -2

assert.equal(evaluate([33, 11, 29, 13], ['/', '-']), -2);

--seed--

--seed-contents--

function evaluate(numbers, operators) {

  return numbers;
}

--solutions--

function doMath(a, b, operator) {
  switch (operator) {
    case "+":
      return a + b;
    case "-":
      return a - b;
    case "*":
      return a * b;
    case "/":
      return a / b;
    default:
      return a % b;
  }
}

function evaluate(numbers, operators) { 
  let total = numbers[0];

  for (let i = 1; i < numbers.length; i++) {
    const operator = operators[(i - 1) % operators.length];
    total = doMath(total, numbers[i], operator);
  }

  return total;
}