检查输入类型......怎么样？ [英] Checking input type...how?

问题描述

我有以下方法：

public void addStudent(){

    String fName, lName;
    double mGrade, fGrade;
    System.out.print("\nEnter first name: ");
    Scanner in = new Scanner(System.in);
    fName = in.nextLine();
    System.out.print("\nEnter last name: ");
    lName = in.nextLine();
    System.out.print("\nEnter midterm grade: ");
    mGrade = in.nextDouble();
    System.out.print("\nEnter final grade: ");
    fGrade = in.nextDouble();
    Student toAdd = new Student(fName, lName, mGrade, fGrade);
    students.add(toAdd);
    System.out.println("\nStudent record added.\n");
    System.out.println(students.size());
}

我如何检查用户是否输入了一个整数以外的中期值成绩和最终成绩？如果他们输入一个非整数，我希望该方法只是请求用户再次键入该值。我猜我必须使用do-while循环。但我不知道如何检查类型......

How can I check if the user typed in something other than an integer for midterm grade and final grade? And if they entered a non-integer, I want the method to just request the user type in that value again. I'm guessing I'll have to use a do-while loop. But I don't don't know how to check the type...

谢谢！

推荐答案

是的，do-while效果最好。

Yes, a do-while will work best.

  int midterm;
  System.out.printLn("Enter midterm grade");
  do
  { 
      try {
          string s = in.nextLine();
          midterm = Integer.parseInt(s);
          break;
      }
      catch (Exception e)
      {
          System.out.printLn("Couldn't parse input, please try again");
      }
  }
  while (true);

这篇关于检查输入类型......怎么样？的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！