Visual Studio C＃2010第四版的练习

Question

我正在一个C＃应用程序上工作，该应用程序应该为每个大罐气体输入行驶的英里数和使用的加仑（整数），然后该应用程序应计算并显示每个大罐的每加仑获得的英里数，并显示为所有的坦克。 我的问题是哨兵控制的方面“ -1”不会阻止程序运行，但是，IDE踢出了JIT调试器，并且我收到了Microsoft.NET Framework异常MileageDriven.exe [732]。

我可以得到一些帮助吗，因为我不想超出本练习范围，因为以后的课程将基于上一课。 提前致谢。 :)

using System;

public class MileagedrivenTest
{
   public static void Main(string[] args)
   {
      Mileage driverMileage = new Mileage("Driver log");

      driverMileage.DisplayMessage();
      driverMileage.DetermineMileagePerGallon();
   } // end main
} // end class MileageDrivenTest

// Fig. 1.1: MileageDriven.cs
// Mileage class that solves mileage per gallon problem
// using sentinel-controlled repetition
using System;

public class Mileage
{
   public string Gallons { get; set; }

   public Mileage (string name)
   {
      Gallons = name;
   }

   public void DisplayMessage()
   {
      Console.WriteLine("Welcome to the mileage log for\n{0}\n", Gallons);
   } // end method DisplayMessage

   //determine the average mileage for gallon per tank of gas
   public void DetermineMileagePerGallon()
   {
      int total = 0;
      int mileage; // sum of miles driven
      int gallons; // sum gallons used
      double average;

      int mileageCounter = 0;

      Console.WriteLine("Enter mileage or -1 to quit: ");
      mileage = Convert.ToInt32(Console.ReadLine());
      Console.WriteLine("Enter gallons used: ");
      gallons = Convert.ToInt32(Console.ReadLine());

      while (mileage != -1)
      {
         mileage = total + mileage;
         mileageCounter = mileageCounter + mileage;

         Console.Write("Enter next miles driven or -1 to quit: ");
         mileage = Convert.ToInt32(Console.ReadLine());         
      } // end while

      if (mileageCounter != 0)
      {
         average = (double)total / mileageCounter;

         Console.WriteLine("\nTotal of the {0} miles driven is {1} per tank is{}", mileageCounter, total);
         Console.WriteLine("Average mile per gallon is {0}", average);
      }
      else
         Console.WriteLine("No mileage entered");      
   }
}

Answer 1

您发布的代码在此行上引发异常：

Console.WriteLine("\nTotal of the {0} miles driven is {1} per tank is{}", mileageCounter, total);

问题是多余的{} 。 如果删除该代码，则该代码将运行，但是我认为它不能解决您要解决的问题。 我根据对问题的解释修改了DefineMileagePerGallon（）-希望它可以使您更接近解决方案：

 //determine the average mileage for gallon per tank of gas
   public void DetermineMileagePerGallon()
   {
       int totalTankfuls = 0;
       int inputMileage;
       int totalMileage = 0; // sum of miles driven
       int totalGallons = 0; // sum gallons used

       Console.WriteLine("Enter mileage or -1 to quit: ");
       while (!Int32.TryParse(Console.ReadLine(), out inputMileage)) ;

       while (inputMileage != -1)
       {
           totalTankfuls++;

           if (inputMileage > 0)
               totalMileage += inputMileage;

           Console.WriteLine("Enter gallons used: ");
           int inputGallons;
           while (!Int32.TryParse(Console.ReadLine(), out inputGallons)) ;

           if (inputGallons > 0)
               totalGallons += inputGallons;

           Console.WriteLine("Enter mileage or -1 to quit: ");
           while (!Int32.TryParse(Console.ReadLine(), out inputMileage)) ;

       } // end while

       if (totalTankfuls > 0)
       {
           double averageMpg = (double)totalMileage / totalGallons;

           double averageMileagePerTankful = (double)totalMileage / totalTankfuls;
           Console.WriteLine("Total of {0} miles driven on {1} tanks of fuel; average is {2} miles per tankful", totalMileage, totalTankfuls, averageMileagePerTankful);
           Console.WriteLine("Average mile per gallon across all tankfuls is {0}", averageMpg);
       }
       else
           Console.WriteLine("No mileage entered");
   }