Problem 5

function frequency() {
  const array = ['a', 'b', 'c', 'd', 'c', 'b', 'b', 'c', 'a', 'e', 'b', 'e'];
  var a = 0;
  var b = 0;
  var c = 0;
  var d = 0;
  var e = 0;
  var most;
  var least;
  //count the occurrences.
  for (var i = 0; i < array.length; i++) {
   switch(array[i]) {
     case 'a':
       a += 1;
       break;
     case 'b':
       b += 1;
       break;
     case 'c':
       c += 1;
       break;
     case 'd':
       d += 1;
       break;
     case 'e':
       e += 1 ;
       break;
   }
  }
  //find the most frequent.
  if (a > b && a > c && a > d && a > e) {
    most = "a";
  } else if (b > a && b > c && b > d && b > e) {
    most = "b";
  } else if (c > a && c > b && c > d && c > e) {
    most = "c";
  } else if (d > a && d > b && d > c && d > e) {
    most = "d";
  } else {
    most = "e";
  }
  //find the least frequent.
  if (a < b && a < c && a < d && a < e) {
    least = "a";
  } else if (b < a && b < c && b < d && b < e) {
    least = "b";
  } else if (c < a && c < b && c < d && c < e) {
    least = "c";
  } else if (d < a && d < b && d < c && d < e) {
    least = "d";
  } else {
    least = "e";
  }
  
  alert("The most frequent item is: " + most + ". " + "The least frequent item is: " + least + ".");
}