7.You Deserved It!


#1


What is wrong?


Your bill is 3.44, and
Oops, try again. false!


function StaffMember(name,discountPercent){
    this.name = name;
    this.discountPercent = discountPercent;
}

var sally = new StaffMember("Sally",5);
var bob = new StaffMember("Bob",10);

// Create yourself again as 'me' with a staff discount of 20%
var me = new StaffMember("Dragan", 20);

var cashRegister = {
    total:0,
    lastTransactionAmount: 0,
    add: function(itemCost){
        this.total += (itemCost || 0);
        this.lastTransactionAmount = 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;
    },
    voidLastTransaction: function(){
        this.total -= this.lastTransactionAmount;
        this.lastTransactionAmount = 0;
    },
    // Create a new method applyStaffDiscount here
  applyStaffDiscount: function(employee) {
   this.total = this.total - this.total*(100-employee.discountPercent)/100;   
  }
    
};

cashRegister.scan('eggs',1);
cashRegister.scan('milk',1);
cashRegister.scan('magazine',3);
// Apply your staff discount by passing the 'me' object 
// to applyStaffDiscount
cashRegister.applyStaffDiscount(me);

// Show the total bill
console.log('Your bill is '+cashRegister.total.toFixed(2));


#2

That error message might be a little mysterious but if you look at the things you "bought" and apply your discount you'll find that the result should be something other than what you're printing


#3

Yes, You are right (result is 13, 74), but I still can't understand why is calculation wrong, and what is wrong in code?


#4

Well you could add more prints so that it shows you what it's doing step by step, allowing you to narrow down which operation isn't what it should be


#5

Instead of:
applyStaffDiscount: function(employee) {
this.total = this.total - this.total*(100-employee.discountPercent)/100;
}
should be:
applyStaffDiscount: function(employee) {
this.total = this.total*(100-employee.discountPercent)/100;
}
Result now is correct, but Oops, try again. false is still here. :slight_smile:


#6

Why is it false? What I should do next?


#7

The exercise doesn't account for rounding errors during floating point operations

Add the end of the discount function, add:

this.total = Number(this.total.toFixed(4))

This doesn't improve the accuracy in any way, it's just rounding after all the operations have been carried out


#8

Thank you. This solved the problem :slight_smile:


#9

This topic was automatically closed 7 days after the last reply. New replies are no longer allowed.