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我看不太懂这题目的意思和指示
希望高手路过能指点一下 <(_ _)>
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题目如下:
Bleep Bleep
The boss looks down at his pager to see Register 8 needs assistance. They
have scanned an item too many times and need to void the last transaction.
So he turns to you and says: "Okay JavaScript Ninja! What do we do now?!"
指示:
We need to keep track of how much the last transaction was. Modify the add
method to keep track of the amount of the last transaction. This should be
tracked in a new property, lastTransactionAmount.
Add a method called voidLastTransaction that subtracts the last amount
transacted from total.
Then use the new method to void the last item we scanned. Finally, scan only
3 of the same item instead.
题目要我们修改的原始码:
var cashRegister = {
total:0,
//Dont forget to add your property
add: function(itemCost) {
this.total += itemCost;
},
scan: function(item,quantity) {
switch (item) {
case "eggs": this.add(0.98 * quantity); break;
case "milk": this.add(1.23 * quantity); break;
case "magazine": this.add(4.99 * quantity); break;
case "chocolate": this.add(0.45 * quantity); break;
}
return true;
},
//Add the voidLastTransaction Method here
};
cashRegister.scan('eggs',1);
cashRegister.scan('milk',1);
cashRegister.scan('magazine',1);
cashRegister.scan('chocolate',4);
//Void the last transaction and then add 3 instead
//Show the total bill
console.log('Your bill is '+cashRegister.total);