Problem

Given an array of integers, write a function that returns the sum of all the odd numbers in the array.
Example input: [1, 2, 3, 4, 5]
Example output: 9

Solution

// Solution:

function sumOfOddNumbers(arr) {
  let sum = 0;
  for (let i = 0; i < arr.length; i++) {
    if (arr[i] % 2 !== 0) {
      sum += arr[i];
    }
  }
  return sum;
}

// Explanation:

// This solution is optimal because it uses a for loop to iterate through the array and check if each number is odd. If it is, it adds it to the sum.
// This solution is optimal because it only iterates through the array once, and it only adds the odd numbers to the sum.