var shops = [{
    captain: "Tim",
    chicken: 150,
    coke: 200,
    fries: 70,
    set: 99,
  },
  {
    captain: "Min",
    chicken: 99,
    coke: 77,
    fries: 55,
    set:101,
  },
  {
    captain: "Mike",
    chicken: 105,
    coke: 111,
    fries: 75,
    set: 130,
  },
];
//陣列資料

var shopsTotal = shops.length; //先抓取店面的資料
console.log(shopsTotal); //結果會得到 3
var cokeTotal = 0; //先預設數量為 0
for (var i = 0 ; i < shopsTotal ; i++) { //從第一個開始迴圈；在店家數以內條件以內；加總
  cokeTotal+= shops[i].coke; //"+=" 要寫在一起，不能空白
  
};

console.log("今年的可樂銷售額為: " + cokeTotal); //結果會得到 今年的可樂銷售額為: 388