如何在for循环中设置限制？

Question

我必须创建一个程序来计算每个学生的平均分数。我设法做到了，但我怎样才能将分数限制在 0 到 100 之间？我搜索了其他问题和许多节目来放置 while 语句。问题是我不知道在哪里添加while。代码如下：

import java.util.Scanner;

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

    int x; // Number of students
    int y; // Number of tests per student
    int Score = 0; //Score of each test for each student
    double Average = 0; //Average score
    double Total = 0; //Total score

    Scanner keyboard = new Scanner(System.in);

    System.out.println("Please enter the number of students: ");
    x = keyboard.nextInt();

    System.out.println("Please enter the amount of test scores per student: ");
    y = keyboard.nextInt();

    for (int z = 0; z < x; z++)
    {           
    System.out.println("Student " + (z + 1));
    System.out.println("------------------------");

    for (int g=0; g < y; g++)
    {
        System.out.print("Please enter score " + (g + 1) + ":  ");

        Total += new Scanner(System.in).nextInt();
        Total += Score;
        Average = (Total/y);
    }       

    System.out.println("The average score for student " + (z + 1) + " is " + Average);
    System.out.println("                      ");

    Total= 0;
    }

    keyboard.close();
}
}

如果有其他方法请说明。提前致谢。

Answer 1

import java.util.Scanner;

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

    int x; // Number of students
    int y; // Number of tests per student
    int Score = 0; //Score of each test for each student
    double Average = 0; //Average score
    double Total = 0; //Total score
    double Input = 0; **//Add this in your variable**
    boolean Valid = false; **//Add this in your variable**

        Scanner keyboard = new Scanner(System.in);

        System.out.println("Please enter the number of students: ");
        x = keyboard.nextInt();

        System.out.println("Please enter the amount of test scores per student: ");
        y = keyboard.nextInt();

        for (int z = 0; z < x; z++)
        {
            System.out.println("Student " + (z + 1));
            System.out.println("------------------------");

            for (int g=0; g < y; g++)
            {
                System.out.print("Please enter score " + (g + 1) + ":  ");
                Input = new Scanner(System.in).nextInt();

                //validation of your input from 0 to 100
                if(Input>=0&&Input<=100)
                {
                    Valid = true;
                }

                //enter while loop if not valid
                while(!Valid)
                {
                    System.out.println("");
                    System.out.print("Please enter a valid score " + (g + 1) + ":  ");
                    Input = new Scanner(System.in).nextInt();
                    if(Input>=0&&Input<=100)
                    {
                        Valid = true;
                    }
                }

                Valid = false; //reset validation;

                Total += Input;
                Average = (Total/y);
            }       

            System.out.println("The average score for student " + (z + 1) + " is " + Average);
            System.out.println("                      ");

            Total= 0;
        }

        keyboard.close();
    }
}

Answer 2

解决此问题的一种简单方法是将用户输入提示放入 while 循环中，并且仅在您验证成绩有效后才退出：

Scanner scanner = new Scanner(System.in);

int score;

while (true) {
    System.out.print("Please enter score " + (g + 1) + ":  ");

    score = scanner.nextInt();

    if (score >= 0 && score <= 100) {
        break;
    }

    System.out.println("Please enter a valid score between 0 and 100!");
}

Total += score;

记得关闭你的Scanners 以避免内存泄漏！