Question

****第二次编辑**** 找出错误处理。但是输出有一个新问题。无论输入什么，数组的所有索引都归零。唯一坚持的指数是最后一个。例如：您在一周内完成的学习时数如下：星期天：0 星期一：0 星期二：0 星期三：0 星期四：0 星期五：0 星期六:(无论用户输入的最后一个号码是什么......这是唯一被保存的索引）

我在参数和方法方面遇到了很多麻烦。我不明白应该去哪里。对我来说这感觉很陌生。无论如何，这是一个家庭作业，但它是一个超级小片。我希望我能得到一些指导，而不是像过去那样得到投票...... 我得到了一个＆＃39; NullReferenceException＆＃34;当调用EnterHours时。

public class StudentUI
{
    int myHours;
    private string[] days = {"Sunday", "Monday", "Tuesday", "Wednesday", "Thursday", "Friday", "Saturday"};
    public StudentUI()
    {
    }

    public void MainMethod()
    {
        Student my = new Student();
        Console.WriteLine("Please enter your name:\t ");
        my.Name = Console.ReadLine();
        Console.WriteLine("Please enter your student ID number:\t ");
        my.ID = int.Parse(Console.ReadLine());
        FillHours(my);
        this.DisplayData(my);
        this.DisplayAverage(my);
    }

    public void FillHours(Student my)
    {
        for (int i = 0; i < this.days.Length; i++)
        {
            Console.Write("Enter the number of hours that you studied ITDEV-115 on {0}:\t ", this.days[i]);
            myHours = int.Parse(Console.ReadLine());
            my.EnterHours(i, myHours);
        }
    }

public void DisplayAverage(Student my)
        {
            Console.Write("\n\nThe average number of hours studied per day was {0:N2}", my.CalculateAverage());

    }

    public void DisplayData(Student my)
    {
        double[] numHours = new double[this.days.Length];
        Console.Clear();
        Console.WriteLine("\n\n\nName: {0}", my.Name);
        Console.WriteLine("ID: {0}", my.ID);
        Console.WriteLine("\n\nThe number of hours of study that you did during the week are as follows:");
        numHours = my.GetNumHours();
        for (int i = 0; i < this.days.Length; i++)
        {
            Console.Write("\t{0}:", this.days[i]);
            Console.WriteLine("\t{0:N2}", numHours[i]);
        }
    }
}

public class Student
{
    private int id;
    private string name;
    private double[] hours;

    public void EnterHours(int index, int myHours)
    {
        hours[index] = myHours;
    }

 public double[] GetNumHours()
        {
            return this.hours;
        }

public double CalculateAverage()
        {
            double num = 0;
            foreach (double number in this.hours)
            {
                num += number;
            }
            return (num / ((double)this.hours.Length));

        }
}

Answer 1

实例字段private double[] hours;最初为null，在这种情况下您无法设置其条目。

您需要创建一个实际的数组对象。

某处您必须hours = new double[length]，其中length是您要创建的新数组的长度。

Answer 2

你可以这样做

requestify.post('https://example.com/', {
    email: 'foo@bar.com'
}, {
    timeout: 60000
})
.then(function(response) {
    var answer = response.getBody();
    console.log("answer:" + answer);
}, function(error) {
    var errorMessage = "Post Failed";
    if(error.code && error.body)
        errorMessage += " - " + error.code + ": " + error.body
    console.log(errorMessage);
    // dump the full object to see if you can formulate a better error message.
    console.log(error);
});

数组具有固定长度，因此您需要在分配任何值之前定义它的大小。如果你看一下Student类的构造函数，我已经超过了被用作数组大小的天数。希望这会有所帮助。

Answer 3

我从一个数组转换为一个列表。

using System;
using System.Collections.Generic;

class StudentUI {
  int myHours;

  private string[] days = { "Sunday", "Monday", "Tuesday", "Wednesday", 
     "Thursday", "Friday", "Saturday" };

  public StudentUI() { }

  public static void Main (string[] args) {
    Student my = new Student();
    Console.WriteLine("Please enter your name:\t ");
    my.Name = Console.ReadLine();

    Console.WriteLine("Please enter your student ID number:\t ");
    my.ID = int.Parse(Console.ReadLine());

    var StudentUI = new StudentUI();
    StudentUI.FillHours(my);
    // DisplayData(my);
    // DisplayAverage(my);
  }


    public void FillHours(Student my) {

      for (int i = 0; i < this.days.Length; i++) {

          Console.Write("Enter the number of hours that you studied ITDEV-115 on {0}:\t ", this.days[i]);
          myHours = int.Parse(Console.ReadLine());
          my.EnterHours(i, myHours);
      }
    }


}

public class Student {
    public int ID;
    public string Name;
    private List<int> Hours = new List<int>();

    public void EnterHours(int index, int myHours) {
      Hours.Add(myHours);
    }
}

在单独的类中将信息传递到数组时遇到问题

3 个答案: