How do i hold the correct output value without roundoff the double value in given program

Question

Given the meal price (base cost of a meal), tip percent (the percentage of the meal price being added as tip), and tax percent (the percentage of the meal price being added as tax) for a meal, find and print the meal's total cost.

Condition: Be sure to use precise values for your calculations, or you may end up with an incorrectly rounded result!

Here is my Program:

static void Main(String[] args)    
{

    double mealCost=Convert.ToDouble(Console.ReadLine());

    int tipPercent=Convert.ToInt32(Console.ReadLine());

    int taxPercent=Convert.ToInt32(Console.ReadLine());

    double tip,tax;

    tip=(mealCost*(tipPercent/100));

    tax=(mealCost*(taxPercent/100));

    double totalCost=mealCost+tip+tax;

    Console.WriteLine("The total meal cost is {0} dollars",totalCost);

    Console.ReadLine();

}

But I had the output as 12.

My Expected output is 15.

If my sample input is 12.00 20 8

My calculation as tip=2.4 and tax=0.96, totalCost=15.36 and the rounded value is (round)totalCost=15.

But the output came as 12.

How do I get the correct output in C#. Can anyone provide me some suggestions to resolve this issue.

Answer 1

What you have to do is, take tipPercent and taxPercent as double values or else implicitly convert them to double before processing division like the following:

tip = (mealCost * ((double)tipPercent / 100));
tax = (mealCost * ((double)taxPercent / 100));

Then you will get totalCost=15.36 for the input specified in the question. Much smarter solution is :

 double mealCost, tipPercent, taxPercent;
 Console.WriteLine("Enter values for Meal Cost, Tip percentage and tax percentage");
 if (!double.TryParse(Console.ReadLine(), out mealCost))
 {
     Console.WriteLine("Invalid input for meal Cost");
 }
 if (!double.TryParse(Console.ReadLine(), out tipPercent))
 {
     Console.WriteLine("Invalid input for Tip percentage");
 }

 if (!double.TryParse(Console.ReadLine(), out taxPercent))
 {
     Console.WriteLine("Invalid input for Tip tax Percent");
 }
 double tip = (mealCost * (tipPercent / 100));
 double tax = (mealCost * (taxPercent / 100));
 double totalCost = mealCost + tip + tax;
 Console.WriteLine("The total meal cost is {0}", totalCost.ToString("C0"));

 Console.ReadLine();