Question

我的代码是用户需要在其间输入标记的位置，然后如果标记不在0到100之间，它必须再次询问，我得到了它的工作，但现在问题陈述：调整上述程序也计算大于或等于50的标记数。

我该怎么做，我已经尝试声明计数整数0但我不确定如何实现这一点。

这是我的代码：

static void Main(string[] args)
{
    int total = 0;
    for (int x = 1; x <= 5; x++)
    {
        Console.WriteLine("Enter your mark");
        int mark = int.Parse(Console.ReadLine());
        if (mark > 100 || mark < 0)
        {
            Console.WriteLine("Invalid mark,Enter your mark again");
            int newmark = int.Parse(Console.ReadLine());
            mark = newmark;
        }
        total += mark;
    }
    Console.WriteLine("sum = " + total);
    double average = (total / 5) * 1.00;
    Console.WriteLine("average = " + average);
    Console.ReadLine();
}

Answer 1

首先，我建议提取方法：不要将所有内容都塞进一个Main中：

   private static int readMark() {
     Console.WriteLine("Enter your mark");

     int result = 0;

     while (true) 
       if (!int.TryParse(Console.ReadLine(), out result))
         Console.WriteLine("Incorrect syntax, enter your mark again");
       else if (result < 0 || result > 100)
         Console.WriteLine("Mark should be in [0..100] range, enter your mark again");   
       else
         return result;
   }

然后让我们将所有标记读入集合，比如一个数组：

   static void Main(string[] args) {
     int[] marks = new int[5];

     for (int i = 0; i < marks.Length; ++i)
       marks[i] = readMark();
   }

现在是统计的时候了。通常我们使用 Linq ：

   static void Main(string[] args) {
     ...
     double average = marks.Average();
     int sum = marks.Sum();
     int countGreaterThan50 = marks.Count(item => item > 50);

但我们可以为此设置一个好的for / foreach循环：

   static void Main(string[] args) {
     ...
     int total = 0;
     countGreaterThan50 = 0;

     for (int i = 0; i < marks.Length; ++i) {
       total += marks[i];

       if (marks[i] > 50) 
         countGreaterThan50 += 1;
     }      

     // (double) total - be careful with integer division:
     // 91 / 5 == 18 when 91.0 / 5 == 18.2  
     double average = ((double) total) / marks.Length;

Answer 2

static void Main(string[] args)
{
  int total = 0;
  int gt50Count = 0;
  for (int x = 1; x <= 5; x++)
  {
    Console.WriteLine("Enter your mark");
    int mark = int.Parse(Console.ReadLine());
    if (mark > 100 || mark < 0)
    {
      Console.WriteLine("Invalid mark,Enter your mark again");
      int newmark = int.Parse(Console.ReadLine());
      mark = newmark;
    }

    total += mark;
    if (mark >= 50)
    {
      gt50Count++;
    }
  }
  Console.WriteLine("sum = " + total);
  double average = (total / 5) * 1.00;
  Console.WriteLine("average = " + average);
  Console.WriteLine("Greater or equal to 50 count = " + gt50Count);
  Console.ReadLine();
}

Answer 3

我会更改您检查标记对while循环无效的方式。只有在检查时，如果用户连续插入无效值，您的代码将接受它。

static void Main(string[] args)
{
    int total = 0;
    int marksAbove50Count = 0;
    for (int x = 1; x <= 5; x++)
    {
        Console.WriteLine("Enter your mark");
        int mark = int.Parse(Console.ReadLine());
        while (mark > 100 || mark < 0)
        {
            Console.WriteLine("Invalid mark,Enter your mark again");
            int newmark = int.Parse(Console.ReadLine());
            mark = newmark;
        }
        total += mark;
        if(mark >= 50) marksAbove50Count++;
    }
    Console.WriteLine("sum = " + total);
    double average = (total / 5) * 1.00;
    Console.WriteLine("average = " + average);
    Console.WriteLine("Marks above 50 count: " + marksAbove50Count);
    Console.ReadLine();
}

C＃：调整程序以计算大于或等于50

3 个答案: