Question

我写了这个程序，将数字等级转换成字母等级，但我一直得到同样的错误。有人能帮我弄清楚我做错了吗？

import static java.lang.System.*; 
import java.util.Scanner;
public class Grade
{
private int numGrade;
 public Grade()
{
Grade test;
 }
public void setGrade(int grade)
{ 
numGrade = grade;
 if (grade >= 90)
{
 System.out.println("A");
 }
{
System.out.println("B");
}
public String getLetterGrade( ) {
  String letGrade="A";
 if (grade>= 90)
{
return letGrade;
}
public String toString(){
return numGrade + " is a " + getLetterGrade() + "\n";
} 
}

Answer 1

使用的语法不正确。

附件是进行转换的示例代码

public class Grade {
    private int numGrade;

    public void setGrade(int grade) {
        numGrade = grade;
        if (grade >= 90) {
            System.out.println("A");
        } else {
            System.out.println("B");
        }
    }

    public String getLetterGrade() {
        String letGrade = "B";
        if (numGrade >= 90) {
            return "A";
        }
        return letGrade;
    }

    public String toString() {
        return numGrade + " is a " + getLetterGrade() + "\n";
    }

}

Answer 2

似乎你试图从许多不同的位置攻击同样的东西。首先让我们从将数字等级转换为字母等级开始，因此在参与输入之前，首先询问用户希望转换的等级类型

    char choise;
    choise = reader.nextChar(); //ask for N or L for numerical or letter

接下来我将展示一个字母到数字转换的示例代码

   public int getNGrade(char grade)
   { 
        if (grade == 'A')
             return 90;
        else if (grade == 'B')
             return 80; //and so on
   }

同样的方法可以用于数字到字母的转换

在主类中你调用函数：

    charGrade = reader.nextChar();
    System.out.println("Your grade in numbers is " + getNGrade(charGrade));

我猜这是你的意思，希望我能提供帮助。

Answer 3

您的代码可以是这样且完美无缺：

public class Grade {

   private int numGrade;

   public Grade(int grade) {
        numGrade = grade;
   }

   public int getGrade() {
       return numGrade;
   }

   public void setGrade(int grade) {
        numGrade = grade;
   }

   public String getLetterGrade() {
       if(numGrade <0 || numGrade > 100) throw new IllegalArgumentException("No such a grade!");

       else if(numGrade>=90) return "A";

       else if (numGrade >= 80) return "B";

       else if(numGrade >= 70) return "C";

       else if(numGrade >= 60) return "D";

       else return "F";

   }

   public String toString(){
        return numGrade + " is a " + getLetterGrade() + "\n";
   } 
}

您可以在同一个类中包含main方法或创建一个单独的类进行测试：

public static void main(String[] args) {
    Grade g = new Grade(75);   //you can enter the grade manually or simply using a Scanner object
    System.out.println(g);
}

Answer 4

import java.util.Scanner;
class Tutorial {
    public static void main(String args[]){
        Scanner input = new Scanner(System.in);     // calling Scanner method
        String restart = "Y";               //initialising the restart variable
        while (restart.equals("Y"))             // testing the conditon(if Y is equals then it continues)
        {
            int grade;
            System.out.println("WELCOME TO ABD GRADING SYSTEM.");           
            System.out.println("Enter your Score(between 1 - 100) : ");                 // Displaying a message on screen
            grade = input.nextInt();                            // Accept Input from the user
            if(grade<=39)
                System.out.println("Your grade is F9");
                else if(grade==40 || grade<=49)
                    System.out.println("Your grade is D7");
            else if(grade==50 || grade<=59)
                System.out.println("Your grade is C6");
            else if(grade==60 || grade<=69)
                System.out.println("Your grade is C5");
            else if(grade==70 || grade<=79)
                System.out.println("Your grade is B2");
            else if(grade==80 || grade<=100)
                System.out.println("Your grade is A1");
            else
            {
                System.out.println("Input Correct score between (1 - 100).");
            }
            System.out.println("THANK YOU.");
            System.out.println("Would you like to Calculate again? Y/N ");
            restart = input.next();
        }
    }       
}

等级检查java

4 个答案: