java - 如何在java中从 double 组创建char数组？

Question

我有一个 double 组，其中包含代表期中考试成绩的值，我需要创建一个具有相同值的 char 数组，但我需要它来显示字母成绩。例如我需要从{89.6,73.9,96.9}到{B,C,A}。这是到目前为止我的代码:

  int numStudents = 60;
      int studNum = 1;
      double[] midtermGrades = new double[numStudents];
      Scanner grades = new Scanner(System.in);
   
      System.out.println("Here are the scores for the most recent test taken by your class:");
      
      
      for (int i = 0; i < midtermGrades.length; i++) {
         midtermGrades[i] = (60 + (double)(Math.random() * 40));
         System.out.printf("Student " + studNum++ + " : " + "%.1f\n", midtermGrades[i]);
      }
      
      double total = 0;
      for (int i = 0; i < midtermGrades.length; i++) {
         total += midtermGrades[i];
      }
      
      double studAvg = (total / midtermGrades.length);
      System.out.printf("The average grade for your class was " + "%.1f\n", studAvg);
       
      int aboveAvg = 0;
                
      for (int i = 0; i < midtermGrades.length; i++) {
         if (midtermGrades[i] > studAvg) {
             aboveAvg++;
         }
      }
      System.out.println("There are " + aboveAvg + " students in your class who scored above the average.\n");
      
     
      
      char[] letterGrades = new char[midtermGrades.length];
      for (int i = 0; i < midtermGrades.length; i++) {
         letterGrades[i] = (char)midtermGrades[i];
               
   }
}

Answer 1

另一种方法是使用 ASCII 表。例如，96.9的第10位是9，字符A和J的十进制值为65，分别为74。因此，可以用74减去9得到字符A对应的十进制值。以下代码片段展示了如何将 double 数组转换为预期的 char 数组:

代码片段

double[] midtermGrades = {89.6, 73.9, 96.9};
char[] letterGrades = new char[midtermGrades.length];
for (int i = 0; i < midtermGrades.length; i++) {
    if (midtermGrades[i] < 60) {
        letterGrades[i] = 'E';
    } else if (midtermGrades[i] >= 90) {
        letterGrades[i] = 'A';
    } else {
        letterGrades[i] = ((char)('J' - (int)midtermGrades[i]/10));
    }
}
System.out.println(Arrays.toString(letterGrades));

控制台输出

[B, C, A]