为什么在 Java 中会出现此错误？ 线程“main”中的异常 java.lang.Error：未解决的编译问题

Question

运行此代码时，我经常收到以下错误：

“线程“主”中的异常“java.lang.Error：未解决的编译问题：无法将线性方程问题解析为类型线性方程问题无法解析为linearequationproblemredo.main的类型（linearequationproblemredo.Z93F725A07423FE1C8896Z86）”

import java.util.Scanner;
public class lineequation {
    private double a;
    private double b;
    private double c;
    private double d;
    private double e;
    private double f;

    public void lineequation(double a, double b, double c, double d, double e, double f) {
        this.a = a;
        this.b = b;
        this.c = c;
        this.d = d;
        this.e = e;
        this.f = f;
    }
    public double getA(){
        return this.a;
    }
    public double getB(){
        return this.b;
    }
    public double getC(){
        return this.c;
    }
    public double getD(){
        return this.d;
    }
    public double getE(){
        return this.e;
    }
    public double getF(){
        return this.f;
    }
    public boolean isSolvable(){
        if(this.a * this.d - this.b * this.c == 0) return false;
        return true;
    }
    public double getX(){
        if(isSolvable()) return ((e * d) - (b * f))/((a * d) - (b * c));
        return -1;
    }
    public double getY(){
        if(isSolvable()) return ((a * f) - (e * c))/((a * d) - (b * c));
        return -1;
    }

    public static void main(String []args){
        Scanner input = new Scanner(System.in);
        System.out.println("Enter a, b, c, d, e, f one at a time starting with a. ");
        double []in = new double[6];
        for(int l = 0; l < 6; l++){
            in[l] = input.nextDouble();
        }
        lineequation test = new lineequation(in[0], in[1], in[2], in[3], in[4], in[5]);
        while(true){

            System.out.println("Type in a-f to show what you have entered OR 'progress' to progress with the script.");
            String t = input.next();

            if(t.equals("progress")) break;
            else if(t.equals("a")) System.out.println(test.getA());
            else if(t.equals("b")) System.out.println(test.getB());
            else if(t.equals("c")) System.out.println(test.getC());
            else if(t.equals("d")) System.out.println(test.getD());
            else if(t.equals("e")) System.out.println(test.getE());
            else if(t.equals("f")) System.out.println(test.getF());
            else System.out.println("Error, please enter a valid input. ");
        }

        while(true){
            System.out.println("To show the output of either x or y, enter 'x' or 'y' or type 'quit' to end the script.");
            String output = input.next();
            if(output.equals("quit")) break;

            try{
                if(!test.isSolvable()) throw new Exception();
                if(output.equals("x")) System.out.println(test.getX());
                else if(output.equals("y")) System.out.println(test.getY());
                else System.out.println("Error, please enter a valid input. ");
            }catch (Exception e){
                System.out.println("The equation has no solution.");
                break;
            }
        }
    }
}

Answer 1

可以通过构造函数实例化 class。 所以你需要将线性方程问题作为构造函数，如下所示。

import java.util.Scanner;
public class lineequation {
    private double a;
    private double b;
    private double c;
    private double d;
    private double e;
    private double f;

    public lineequation(double a, double b, double c, double d, double e, double f) {
        this.a = a;
        this.b = b;
        this.c = c;
        this.d = d;
        this.e = e;
        this.f = f;
    }
    public double getA(){
        return this.a;
    }
    public double getB(){
        return this.b;
    }
    public double getC(){
        return this.c;
    }
    public double getD(){
        return this.d;
    }
    public double getE(){
        return this.e;
    }
    public double getF(){
        return this.f;
    }
    public boolean isSolvable(){
        if(this.a * this.d - this.b * this.c == 0) return false;
        return true;
    }
    public double getX(){
        if(isSolvable()) return ((e * d) - (b * f))/((a * d) - (b * c));
        return -1;
    }
    public double getY(){
        if(isSolvable()) return ((a * f) - (e * c))/((a * d) - (b * c));
        return -1;
    }

    public static void main(String []args){
        Scanner input = new Scanner(System.in);
        System.out.println("Enter a, b, c, d, e, f one at a time starting with a. ");
        double []in = new double[6];
        for(int l = 0; l < 6; l++){
            in[l] = input.nextDouble();
        }
        lineequation test = new lineequation(in[0], in[1], in[2], in[3], in[4], in[5]);
        while(true){

            System.out.println("Type in a-f to show what you have entered OR 'progress' to progress with the script.");
            String t = input.next();

            if(t.equals("progress")) break;
            else if(t.equals("a")) System.out.println(test.getA());
            else if(t.equals("b")) System.out.println(test.getB());
            else if(t.equals("c")) System.out.println(test.getC());
            else if(t.equals("d")) System.out.println(test.getD());
            else if(t.equals("e")) System.out.println(test.getE());
            else if(t.equals("f")) System.out.println(test.getF());
            else System.out.println("Error, please enter a valid input. ");
        }

        while(true){
            System.out.println("To show the output of either x or y, enter 'x' or 'y' or type 'quit' to end the script.");
            String output = input.next();
            if(output.equals("quit")) break;

            try{
                if(!test.isSolvable()) throw new Exception();
                if(output.equals("x")) System.out.println(test.getX());
                else if(output.equals("y")) System.out.println(test.getY());
                else System.out.println("Error, please enter a valid input. ");
            }catch (Exception e){
                System.out.println("The equation has no solution.");
                break;
            }
        }
    }
}

Answer 2

我认为您在 Java 中是全新的。 一个好的起点是Java 教程，然后转到Oracle Java 教程

此代码无法编译，这些是问题：

1. class 名称为lineequation ，构造函数名称为linearequationproblem ，这是不允许的。 在 Java class 名称和构造函数名称应该相同，因为构造函数是创建 class 实例和初始化成员变量的特殊方法。

2. 第 56 行： java linearequationproblem test = new linearequationproblem(in[0], in[1], in[2], in[3], in[4], in[5]); 您正在尝试创建线性方程问题的实例，但这种类型（类）不存在。

3. private double f;`该反引号是不合法的，并且将无法编译，因为这不是正确的语法。

有关 Java 的更多详细信息，您可以参考上面的文档。 享受学习！