Javascript JS Codecademy Return II-随Return一起发布

我对以下代码有问题。当它运行时，它会记录我的三个订单，但我得到的小计是0。它应该将orderCount的3乘以7.5，因为我调用了函数takeOrder三次。我遗漏了什么吗

var orderCount = 0;

function takeOrder(topping, crustType){
    orderCount + 1;
    console.log("Order: " + crustType + " pizza topped with " + topping + ".");
}

function getSubTotal(itemCount) {
    return itemCount * 7.5;
}

takeOrder("mushroom", "stuff crust");

takeOrder("pepperoni", "thin crust");

takeOrder("sausage", "sicilian crust");

console.log(getSubTotal(orderCount));

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您需要增加订单数量

orderCount += 1;

不会增加

orderCount

的值

使用

相反，它是

orderCount += 1;

orderCount = orderCount + 1;

它是

orderCount += 1;

orderCount = orderCount + 1;

更改订单计数+1；到orderCount++

var orderCount = 0;

function takeOrder(topping, crustType){
    orderCount ++;
    console.log("Order: " + crustType + " pizza topped with " + topping + ".");
}

function getSubTotal(itemCount) {
    return itemCount * 7.5;
}

takeOrder("mushroom", "stuff crust");

takeOrder("pepperoni", "thin crust");

takeOrder("sausage", "sicilian crust");

console.log(getSubTotal(orderCount));