java - 需要从数字列表中显示最高和最低成绩

Question

我需要输入成绩列表，并在输入字符时让代码停止。然后它会显示最高等级和最低等级。

我创建了一个while循环，但是当我运行代码时，它一直循环并且不会停止。

public class MaxMinGrades{
  public static void main(String[] args){
    double maxGrade = Double.MAX_VALUE;
    double minGrade = Double.MIN_VALUE;
    Scanner input = new Scanner(System.in);
    System.out.println("Enter as many student grades as you like. Enter a character to stop.");
    double grades = input.nextDouble();

    while(input.hasNextDouble()) {
      if (grades > maxGrade) {
        maxGrade = grades;
      }
      if (grades < minGrade) {
        minGrade = grades;
      }
    }
    System.out.println("The highest grade is: " + maxGrade);
    System.out.println("The lowest grade is: " + minGrade);
  }
}

我会输入:50 66.85 73.5 78.9 77 q.

输出为:最高等级为:78.9最低等级为:50.0

Answer 1

public class MaxMinGrades{
  public static void main(String[] args){
    double maxGrade = 0.0;
            double minGrade = 100.0;
            Scanner input = new Scanner(System.in);
            System.out.println("Enter as many student grades as you like. Enter a character to stop.");


            while(input.hasNextDouble()) {
            double grades = input.nextDouble();
              if (grades > maxGrade) {
                maxGrade = grades;
              }
              if (minGrade > grades) {
                minGrade = grades;
              }
            }
            System.out.println("The highest grade is: " + maxGrade);
            System.out.println("The lowest grade is: " + minGrade);
  }
}

这样，while 循环内部就有了中断条件。当某些内容发生变化时，将检查 boolean 条件。