Java &引用；错误：找不到符号"；关于继承相关程序

我收到一条消息说

错误：找不到关于
c1的符号
。certificateAwarded（等级）语句。我不知道是什么问题。我真的需要所有能得到的帮助

代码如下：

ExamDetails.java

package Exams;

import javax.swing.JOptionPane;

public class ExamDetails {

    public static void main(String[] args) {

        StudentResults sr = new StudentResults();
        sr.inputStudentName();
        sr.inputExamName();
        sr.inputScore();
        sr.inputGrade();
        sr.DisplayDetails();

        Certificates c1 = new Certificates();
        c1.certificateAwarded(grade);
    }

}

package Exams;

import javax.swing.JOptionPane;

public class StudentResults {

    private String fullname;
    private String examName;
    private int examScore;
    private int examGrade;

    public String getStudentName()
    {
        return fullname;
    }

    public void setStudentName(String name)
    {
        fullname = name;
    }

    public String getExamName()
    {
        return examName;
    }

    public void setExamName(String exam)
    {
        examName = exam;
    }

    public int getExamScore()
    {
        return examScore;
    }

    public void setExamScore(int score)
    {
        examScore = score;
    }

    public int getExamGrade()
    {
        return examGrade;
    }

    public void setExamGrade(int grade)
    {
        examGrade = grade;
    }

    public void inputStudentName()
    {
        fullname  = JOptionPane.showInputDialog("Enter the student's name");
    }

    public void inputExamName()
    {
        examName  = JOptionPane.showInputDialog("Enter the subject's name");
    }

    public void inputScore()
    {
        String scoreString = new String();
        JOptionPane.showInputDialog("Enter the student's score");
        examScore = Integer.parseInt(scoreString);
    }

    public void inputGrade()
    {
        String gradeString = new String();
        JOptionPane.showInputDialog("Enter the student's grade");
        examGrade = Integer.parseInt(gradeString);
    }

    public String DisplayDetails()
    {
        String d;
        d = "Student Name : " + fullname + "Exam Name : " + examName + "Score : " + examScore + "Grade : " + examGrade;
        return d;
    }
}

package Exams;

public class Certificates extends StudentResults {

    private String certificate;
    public String Grade;

    Certificates()
    {
        super();
        certificate = "No Certificate Awarded";
    }

    String certificateAwarded(/*int grade*/) {

        //StudentResults g = new StudentResults();
        //Grade = g.inputGrade();
        //Grade = inputGrade(examGrade);

        if(Grade.equals("Grade : A"))
        {
            this.certificate = "Certificate of Excellence";
        }
        else
            if(Grade.equals("Grade : B"))
            {
                this.certificate = "Certificate of Achievement";
            }
            else
                if(Grade.equals("Grade : C"))
                {
                    this.certificate = "Certificate of Achievement";
                }
                else
                    this.certificate = "No Certificate Awardedt";

           return this.certificate;
    }  
}

StudentResults.java

package Exams;

import javax.swing.JOptionPane;

public class ExamDetails {

    public static void main(String[] args) {

        StudentResults sr = new StudentResults();
        sr.inputStudentName();
        sr.inputExamName();
        sr.inputScore();
        sr.inputGrade();
        sr.DisplayDetails();

        Certificates c1 = new Certificates();
        c1.certificateAwarded(grade);
    }

}

package Exams;

import javax.swing.JOptionPane;

public class StudentResults {

    private String fullname;
    private String examName;
    private int examScore;
    private int examGrade;

    public String getStudentName()
    {
        return fullname;
    }

    public void setStudentName(String name)
    {
        fullname = name;
    }

    public String getExamName()
    {
        return examName;
    }

    public void setExamName(String exam)
    {
        examName = exam;
    }

    public int getExamScore()
    {
        return examScore;
    }

    public void setExamScore(int score)
    {
        examScore = score;
    }

    public int getExamGrade()
    {
        return examGrade;
    }

    public void setExamGrade(int grade)
    {
        examGrade = grade;
    }

    public void inputStudentName()
    {
        fullname  = JOptionPane.showInputDialog("Enter the student's name");
    }

    public void inputExamName()
    {
        examName  = JOptionPane.showInputDialog("Enter the subject's name");
    }

    public void inputScore()
    {
        String scoreString = new String();
        JOptionPane.showInputDialog("Enter the student's score");
        examScore = Integer.parseInt(scoreString);
    }

    public void inputGrade()
    {
        String gradeString = new String();
        JOptionPane.showInputDialog("Enter the student's grade");
        examGrade = Integer.parseInt(gradeString);
    }

    public String DisplayDetails()
    {
        String d;
        d = "Student Name : " + fullname + "Exam Name : " + examName + "Score : " + examScore + "Grade : " + examGrade;
        return d;
    }
}

package Exams;

public class Certificates extends StudentResults {

    private String certificate;
    public String Grade;

    Certificates()
    {
        super();
        certificate = "No Certificate Awarded";
    }

    String certificateAwarded(/*int grade*/) {

        //StudentResults g = new StudentResults();
        //Grade = g.inputGrade();
        //Grade = inputGrade(examGrade);

        if(Grade.equals("Grade : A"))
        {
            this.certificate = "Certificate of Excellence";
        }
        else
            if(Grade.equals("Grade : B"))
            {
                this.certificate = "Certificate of Achievement";
            }
            else
                if(Grade.equals("Grade : C"))
                {
                    this.certificate = "Certificate of Achievement";
                }
                else
                    this.certificate = "No Certificate Awardedt";

           return this.certificate;
    }  
}

Certificates.java

package Exams;

import javax.swing.JOptionPane;

public class ExamDetails {

    public static void main(String[] args) {

        StudentResults sr = new StudentResults();
        sr.inputStudentName();
        sr.inputExamName();
        sr.inputScore();
        sr.inputGrade();
        sr.DisplayDetails();

        Certificates c1 = new Certificates();
        c1.certificateAwarded(grade);
    }

}

package Exams;

import javax.swing.JOptionPane;

public class StudentResults {

    private String fullname;
    private String examName;
    private int examScore;
    private int examGrade;

    public String getStudentName()
    {
        return fullname;
    }

    public void setStudentName(String name)
    {
        fullname = name;
    }

    public String getExamName()
    {
        return examName;
    }

    public void setExamName(String exam)
    {
        examName = exam;
    }

    public int getExamScore()
    {
        return examScore;
    }

    public void setExamScore(int score)
    {
        examScore = score;
    }

    public int getExamGrade()
    {
        return examGrade;
    }

    public void setExamGrade(int grade)
    {
        examGrade = grade;
    }

    public void inputStudentName()
    {
        fullname  = JOptionPane.showInputDialog("Enter the student's name");
    }

    public void inputExamName()
    {
        examName  = JOptionPane.showInputDialog("Enter the subject's name");
    }

    public void inputScore()
    {
        String scoreString = new String();
        JOptionPane.showInputDialog("Enter the student's score");
        examScore = Integer.parseInt(scoreString);
    }

    public void inputGrade()
    {
        String gradeString = new String();
        JOptionPane.showInputDialog("Enter the student's grade");
        examGrade = Integer.parseInt(gradeString);
    }

    public String DisplayDetails()
    {
        String d;
        d = "Student Name : " + fullname + "Exam Name : " + examName + "Score : " + examScore + "Grade : " + examGrade;
        return d;
    }
}

package Exams;

public class Certificates extends StudentResults {

    private String certificate;
    public String Grade;

    Certificates()
    {
        super();
        certificate = "No Certificate Awarded";
    }

    String certificateAwarded(/*int grade*/) {

        //StudentResults g = new StudentResults();
        //Grade = g.inputGrade();
        //Grade = inputGrade(examGrade);

        if(Grade.equals("Grade : A"))
        {
            this.certificate = "Certificate of Excellence";
        }
        else
            if(Grade.equals("Grade : B"))
            {
                this.certificate = "Certificate of Achievement";
            }
            else
                if(Grade.equals("Grade : C"))
                {
                    this.certificate = "Certificate of Achievement";
                }
                else
                    this.certificate = "No Certificate Awardedt";

           return this.certificate;
    }  
}

在ExamDetails.java类中，您不会声明或实例化传递给
certificateAwarded
方法的
grade
变量

另外，在Certificates.java类中注释掉了参数。您应该取消对参数的注释。
要编译代码，
grade
必须是

在main方法中声明的局部变量
ExamDetails类上定义的字段
这两个声明都不存在，因此编译器告诉您它找不到等级“符号”

尝试添加
int grade=sr.getExamGrade（）或类似内容。
正如评论所建议的，您需要声明“等级”。没有它，编译器就无法完成确定Certificates.certificateAwarded的签名，因为参数列表中的内容是签名的一部分。更重要的是，代码中包含以下内容：

向上的字符串证书（/*int grade*/）

参数“int grade”被注释掉。因此，编译器看到：

字符串证书向前（）

因此，编译器可能告诉您的是，它正在寻找一个名为certificateAwarded的证书方法，该方法接受1个类型为{无论“grade”是什么类型的}的参数。它没有发现

我说“可能是”是因为你在问题行中缺少两个符号：等级和一个带有匹配签名的方法

我可以想到两件事，你可以尝试修复它：

将“c1.certificateAwarded（等级）；”更改为“c1.certificateAwarded（）；”
将“等级”声明为main中某个位置（或main中可见的位置）的int，并将“String certificateAwarded（/int grade/）”更改为“String certificateAwarded（int grade）”

我会先尝试第一种选择。如果有必要尝试第二种方法，您需要在main（或main可以看到等级的位置）和certificateAwarded方法中添加额外的代码。
哪里声明了等级？
等级未声明。完整的错误消息是什么？Hi@PaulBoddington、@Kami和@iamnotmaynard。我刚刚删除了
等级
，但现在程序在输入（从字符串到int）后停止。在“inputScore”语句中。为什么会这样？感谢各位的回复。正如9Deuce提到的，一旦你修复了这个问题，你发布的代码将产生其他编译器错误，即使在添加了这个答案中建议的行时也是如此。我尝试了这个语句，但仍然出现了错误，所以我只是删除了
等级
。但另一件事困扰着我，程序在输入（从字符串到int）后停止。在“inputScore”语句中。为什么会这样？谢谢你的回复。请注意，“等级”与“等级”是不同的变量。Java区分大小写。我刚刚删除了
等级
。但另一件事困扰着我，程序在输入（从字符串到int）后停止。在“inputScore”语句中。为什么会这样？谢谢你的回复。我刚刚删除了
等级
。但另一件事困扰着我，程序在输入（从字符串到int）后停止。在“inputScore”语句中。为什么会这样？谢谢您的回复。@JwanRadzi，因为您没有将从
JOptionPane
中拉入的值赋给任何东西。查看此站点，您正在将空白
字符串
解析为
整数