exercises.js

// Write a function named allEven that accepts an array of
// numbers and returns true if every number is even, false
// otherwise. Use the forEach method to solve
// this problem

function allEven(list) {
  var result = true;
  list.forEach(function(element) {
    if (element % 2 != 0) {
      result = false;
    }
  });
  return result;
}

// Write a function named isMember that accepts two
// arguments—an array of strings and a string—and returns true if
// the string is contained in the array, false otherwise. Use the forEach method to solve
// this problem.

function isMember(list, element) {
  var result = false;
  list.forEach(function(el) {
    if (element == el) {
      result = true;
    }
  });
  return result;
}

// Write a function named hasOneEven that accepts an array of 
// numbers and returns true if it contains at least one even number. 
// Use the forEach method to solve this problem.

function hasOneEven(list) {
  var result = false;
  list.forEach(function(element) {
    if (element % 2 == 0) {
      result = true;
    }
  });
  return result;
}

// Write a function named countVowels that accepts a string
// representing a sentence and returns the number of vowels
// contained in the sentence. Use the forEach method to solve
// this problem
function countVowels(string) {
  var count = 0;
  string.split("").forEach(function(letter) {
    if (isMember(["a", "e", "i", "o", "u"], letter.toLowerCase())) {
      count++;
    }
  });
  return count;
}