(HackerRank Day 2: Operators) Problem with Constructor

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In this HackerRank challenge, I need to find the total meal cost by adding tip_percent which is 20% of the meal_cost and tax_percent which is 8% of the meal_cost and the meal_cost being $12. So the output must be a round number of 15 but my output comes out as $14.

It does seem to work properly with custom values like $12.50 for meal_cost which later totaled comes out as a rounded value of $16. What am I doing wrong here?

static double findMealTotal(double meal_cost, int tip_percent, int tax_percent) {

    tip_percent = (int)(meal_cost * tip_percent)/100;
     tax_percent = (int)(meal_cost * tax_percent)/100;
      return meal_cost + tip_percent + tax_percent;
}

private static final Scanner scanner = new Scanner(System.in);

public static void main(String[] args) {
    double meal_cost = scanner.nextDouble();
    int tip_percent = scanner.nextInt();
    int tax_percent = scanner.nextInt();

    //changed solve to mealTotal
    double mealTotal = findMealTotal(meal_cost, tip_percent, tax_percent);

    System.out.println(Math.round(mealTotal));

    scanner.close();
}

Answer

You are using integers. Integers are rounded, so you loose precision over the next calculation. Try using doubles and cast to int at the end.

    static void Main(string[] args)
    {
        double cost = findMealTotal(12, 20, 8);
        Console.WriteLine(cost.ToString());
    }

    static double findMealTotal(double meal_cost, int tip_percent, int tax_percent)
    {
        double tip = meal_cost * tip_percent / 100;
        double tax = meal_cost * tax_percent / 100;
        return meal_cost + tip + tax;
    }

And don’t reuse parameters inside your function. It is bad practice.



Source: stackoverflow