Question

使用读取的switch语句名称GradeReport编写程序   来自用户的成绩并相应地打印评论。

说明：提示用户输入他们的成绩用户必须提示   如果输入不是整数，则输入数字等级（0到100）   在0到100之间，提示用户重新输入

如果不满足条件，请使用do循环重新输入等级   或等级不在0到100之间，然后在屏幕上提示用户   如下（“错误：您必须输入0到100之间的整数”）;“

还包含一个while循环来跟踪尝试。创建一个   变量名称“尝试”将跟踪尝试不超过3   因此，如果输入不是0到100之间的整数，则提示输入   用户重新输入

我有一个问题是找出while循环以跟踪尝试。

这就是我所拥有的：

import java.util.Scanner;

public class GradeReport {
 public static void main(String[] args) {

  int grade, category;

  Scanner scan = new Scanner(System.in);
  do {
   System.out.println("Enter a numeric grade (0 to 100): ");
   grade = scan.nextInt();
   if (grade >= 0 && grade <= 100)
    break;
   System.out.println("Error: You must re-enter an integer between 0 and 100");
  } while (true);

  int tries = 1;
  while (tries <= 3) {
   System.out.println("Tries: " + tries);
   tries++;

   category = grade / 10;

   System.out.print("That grade is ");
   switch (category) {
    case 10:
     System.out.println("a perfect score. Well done.");
     break;
    case 9:
     System.out.println("well above average. Excellent.");
     break;
    case 8:
     System.out.println("above average. Nice job.");
     break;
    case 7:
     System.out.println("average.");
     break;
    case 6:
     System.out.println("below average. You should see the");
     System.out.println("instructor to clarify the material " + "presented in class.");
     break;
    default:
     System.out.println("not passing.");
   }
  }
 }
}

Answer 1

这是您尝试的部分：

do {
    System.out.println("Enter a numeric grade (0 to 100): ");
    grade=scan.nextInt();
    if(grade>=0 && grade<=100)
    break;
    System.out.println ("Error: You must re-enter an integer between 0 and 100");   
    }while(true);

这是您认为计算尝试次数的部分：

    int tries = 1;
    while (tries <= 3) {
         System.out.println("Tries: " + tries);
         tries++;
         ...

You need to define `int tries = 0;` before trying, and integrate the incrementation inside the loop where you actually try. I'm sure you can figure out the rest yourself. You seem to be pretty close :)

编辑：由于其他人试图给你完整答案（而且不太好），我会这样做： import java.util.Scanner;

public class GradeReport {
    public static void main(String[] args) {

        int grade, category;

        int tries = 0;

        Scanner scan = new Scanner(System.in);
        do {
            tries++;
            System.out.println("Enter a numeric grade (0 to 100): ");
            grade = scan.nextInt();
            if(grade >= 0 && grade <= 100){
                break;
            }
            System.out.println("attempt " + tries + " unsuccessful");
            if(tries >= 3){
                System.out.println("No more attempts.");
                break;
            }
            System.out.println("Error: You must re-enter an integer between 0 and 100");

        } while (true);

        if(grade >= 0 && grade <= 100){

            category = grade / 10;

            System.out.print("That grade is ");
            switch (category) {
            case 10:
                System.out.println("a perfect score. Well done.");
                break;
            case 9:
                System.out.println("well above average. Excellent.");
                break;
            case 8:
                System.out.println("above average. Nice job.");
                break;
            case 7:
                System.out.println("average.");
                break;
            case 6:
                System.out.println("below average. You should see the");
                System.out.println("instructor to clarify the material " + "presented in class.");
                break;
            default:
                System.out.println("not passing.");
            }
        }
    }
}

Answer 2

您只需在循环输入之前设置tries变量：

    Scanner scan = new Scanner (System.in);
    int tries = 0;
    do
    {
        System.out.println("Enter a numeric grade (0 to 100): ");
        grade=scan.nextInt();
        if(grade>=0 && grade<=100)
            break;
        tries += 1;
        System.out.println ("Error: You must re-enter an integer between 0 and 100");   
        }while(tries < 3);

    System.out.println("Tries: " + (tries + 1));

Answer 3

试试此代码

int grade, category;

    Scanner scanner = new Scanner(System.in);
    int tries = 0;
    do{
        System.out.print("Enter a numeric grade (0 to 100): ");
        grade = scanner.nextInt();
        if(grade<0 || grade>100){
            System.out.println ("Error: You must re-enter an integer between 0 and 100");
        } else {
            break;
        }
        tries++;
    } while (tries < 3);
    System.out.print(grade);

在您拥有以下代码的地方

int grade, category;

        Scanner scan = new Scanner (System.in);
        do
        {
            System.out.println("Enter a numeric grade (0 to 100): ");
            grade=scan.nextInt();
            if(grade>=0 && grade<=100)
                break;
            System.out.println ("Error: You must re-enter an integer between 0 and 100");   
            }while(true);

        int tries = 1;
        while (tries <= 3) {
            System.out.println("Tries: " + tries);
            tries++;

如何使while循环跟踪尝试？

3 个答案: