// 1
// 创建一个记录学生成绩的对象，提供一个添加成绩的方法，以及一个显示学生平均成绩的方法。
function createTranscript() {
  this.gradeList = [];
  this.add = (num) => {
    this.gradeList.push(num);
  };
  this.calcAvge = () => {
    const sum = this.gradeList.reduce((sum, grade) => {
      sum += grade;
      return sum;
    }, 0);
    return sum / this.gradeList.length;
  };
}

const transcript1 = new createTranscript();
transcript1.add(120);
transcript1.add(80);
console.log(transcript1.calcAvge());

// 2
// 将一组单词存储在一个数组中，并按正序和倒序分别显示这些单词
const list = ["fan", "sheng", "fa", "lan", "xiu", "ping"];
for (let i = 0; i < list.length; i++) {
  console.log(list[i]);
}
console.log("--------------------------")
for (let i = list.length - 1; i >= 0; i--) {
  console.log(list[i]);
}

// 3
function weekTemps() {
  this.dataStore = [];
  for (let i = 0; i < 12; i++) {
    this.dataStore.push([])
  }
  this.add = add;
  this.average = average;
}

function add(month, temp) {
  this.dataStore[month].push(temp);
}

function average() {
  var total = 0;
  for (var i = 0; i < this.dataStore.length; ++i) {
     total += this.dataStore[i];
  }
  return total / this.dataStore.length;
}

var thisWeek = new weekTemps();
thisWeek.add(52);
thisWeek.add(55);
thisWeek.add(61);
thisWeek.add(65);
thisWeek.add(55);
thisWeek.add(50);
thisWeek.add(52);
thisWeek.add(49);
print(thisWeek.average()); // displays 54.875