Question

所以我有这段代码：

import java.util.Scanner;

public class StudentGradeDriver
{

public static void main(String[] args) 
{
    Scanner scanner = new Scanner(System.in);

    System.out.println("Enter student name: ");
    String name = scanner.nextLine();
    StudentGrade grade = new StudentGrade(name);  

    System.out.println("Welcome to the Student Grade Interface!");
    System.out.println("You are modyfing the grades for John Doe");
    System.out.println("===============================================");
    System.out.println("(1)  Add homework score");
    System.out.println("(2)  Add passed Lab");
    System.out.println("(3)  Add midterm exam score");
    System.out.println("(4)  Set final exam score");
    System.out.println("(5)  Calculate final grade");
    System.out.println("(-1) Exit");
    System.out.println("===============================================");
    System.out.print("Please input your choice: ");
    int choice = scanner.nextInt();

while(true)
{  
   if (choice == 1);
  {
      System.out.println("Enter total points earned: ");
      double _hwEarned = scanner.nextDouble();

      System.out.println("Enter total points possible: ");
      double _hwPossible = scanner.nextDouble();

      grade.addHomework(_hwEarned, _hwPossible);

      System.out.println("Welcome to the Student Grade Interface!");
      System.out.println("You are modyfing the grades for John Doe");
      System.out.println("===============================================");
      System.out.println("(1)  Add homework score");
      System.out.println("(2)  Add passed Lab");
      System.out.println("(3)  Add midterm exam score");
      System.out.println("(4)  Set final exam score");
      System.out.println("(5)  Calculate final grade");
      System.out.println("(-1) Exit");
      System.out.println("===============================================");
      System.out.print("Please input your choice: ");
      choice = scanner.nextInt();
  }

  if (choice == 2)
  {
      System.out.println("A passed lab has been added for "
                             + "this student. ");

      grade.passedLab();
  }

  else if (choice == 3)
  {
      System.out.println("Enter total points earned for midterm: ");
      double _midEarned = scanner.nextDouble();

      System.out.println("Enter total points possible for midterm: ");
      double _midPossible = scanner.nextDouble();

      grade.addExam(_midEarned, _midPossible);

      System.out.println("Welcome to the Student Grade Interface!");
    System.out.println("You are modyfing the grades for John Doe");
    System.out.println("===============================================");
    System.out.println("(1)  Add homework score");
    System.out.println("(2)  Add passed Lab");
    System.out.println("(3)  Add midterm exam score");
    System.out.println("(4)  Set final exam score");
    System.out.println("(5)  Calculate final grade");
    System.out.println("(-1) Exit");
    System.out.println("===============================================");
    System.out.print("Please input your choice: ");
    choice = scanner.nextInt();

  } 

  else if (choice == 4)
  {
      System.out.println("Enter total points earned for final: ");
      double _finalEarned = scanner.nextDouble();

      grade.setFinalExam(_finalEarned);

    System.out.println("Welcome to the Student Grade Interface!");
    System.out.println("You are modyfing the grades for John Doe");
    System.out.println("===============================================");
    System.out.println("(1)  Add homework score");
    System.out.println("(2)  Add passed Lab");
    System.out.println("(3)  Add midterm exam score");
    System.out.println("(4)  Set final exam score");
    System.out.println("(5)  Calculate final grade");
    System.out.println("(-1) Exit");
    System.out.println("===============================================");
    System.out.print("Please input your choice: ");
    choice = scanner.nextInt();
  }

  else if (choice == 5)
  {
      System.out.println("The score for " + name + " is " 
                             + grade.getFinalScore());
  }
  else if(choice == -1)
  {
      break;
  }
 }

  }
 }

是否有更简单或其他方式循环播放，以便菜单显示在选项1,3,4和5之后，但不是2，并在用户输入为-1时仍然退出？即使我复制并粘贴菜单，似乎if（选项== 1）仍然在我按下不同的数字后执行。执行完后，菜单再次弹出，如果我点击相同的数字，它将执行。例如，当我的第一个选择是3时，但它只会执行if（choice == 1），我的第二个选择将是2并且将执行if（choice == 2），而我的第三个选择将再次为3 ，但它会回到if（选择== 1），有人会知道为什么会这样吗？任何帮助将不胜感激。

Answer 1

不太确定你要做什么，但我看到你有一个while循环，如果声明与你的第二选择if语句分开，你的第一选择。如果（选择== 2）或者我误解了你想要做什么，你的意思是做其他事吗？

在选择后循环显示菜单

1 个答案: