Android JustJava应用calculatePrice方法计算逻辑错误排查求助

Hey there! Let's get that price calculation sorted out—your issue is a classic case of accidental double multiplication, plus a tiny typo in your topping checks. Here's what's going wrong and how to fix it:

The Root Cause of the Wrong Totals #

Looking at your calculatePrice method, you're making two critical mistakes:

1. Double Multiplying by Quantity:
   You first calculate basePrice = quantity *5 (which already accounts for the number of coffees), but then at the end you return quantity * basePrice. That means you're squaring the quantity before multiplying by 5! For example:

   • Quantity = 2: 2*5 =10, then 2*10=20 (instead of the correct 10)
   • Quantity =3: 3*5=15, then 3*15=45 (instead of the correct15)

2. Incorrect Topping Check:
   You used addChocolate for both the whipped cream and chocolate topping checks. That means whipped cream never adds its $1 charge, and chocolate gets charged $3 (1+2) instead of just $2.

Corrected calculatePrice Method #

Replace your existing calculatePrice method with this fixed version:

private int calculatePrice(boolean addWhippedCream, boolean addChocolate ) {
    // Price of 1 cup of coffee, multiplied by quantity
    int basePrice = quantity *5;
    // Add $1 per coffee if the user wants whipped cream
    if (addWhippedCream) {
        basePrice += 1 * quantity;
    }
    // Add $2 per coffee if the user wants chocolate
    if (addChocolate) {
        basePrice += 2 * quantity;
    }
    // Return the total price (no extra multiplication needed!)
    return basePrice;
}

Note: I updated the topping charges to multiply by quantity—this ensures you charge for toppings per coffee, which makes sense for a coffee order. If you intended to charge a flat topping fee regardless of quantity, just remove the * quantity part from those lines.

Bonus: Small Polishing Fixes #

While we're at it, here are a couple of minor tweaks for your creatOrderSummary method to make it cleaner:

• Change Totall to Total (spelling error)
• Capitalize "Add chocolate?" to match the whipped cream line
• Add a colon and space after \nQuantity so it reads neatly: \nQuantity: " + quantity

Testing the Fix #

After making these changes:

• Quantity 1 will return $5 (or $6 with whipped cream, $7 with chocolate, $8 with both)
• Quantity 2 will return $10 (or $12 with whipped cream, $14 with chocolate, $16 with both)
• Quantity3 will return $15 (as expected!)

That should resolve your calculation issues completely. Let me know if you run into any other snags!

内容的提问来源于stack exchange，提问作者Mostafa