编译器错误：“预期的类、接口或枚举”

java compiler-errors

2022-09-02 23:51:28

我已经对此程序进行了几个小时的故障排除，尝试了几种配置，并且没有运气。它是用java编写的，并且有33个错误（从之前的50个降低）

源代码：

/*This program is named derivativeQuiz.java, stored on a network drive I have permission to edit
The actual code starts below this line (with the first import statement) */
import java.util.Random;
import java.Math.*;
import javax.swing.JOptionPane;
public static void derivativeQuiz(String args[])
{
    // a bunch of code
}

错误日志（在 JCreator 中编译）：

--------------------Configuration: <Default>--------------------
H:\Derivative quiz\derivativeQuiz.java:4: class, interface, or enum expected
public static void derivativeQuiz(String args[])
              ^
H:\Derivative quiz\derivativeQuiz.java:9: class, interface, or enum expected
    int maxCoef = 15;
    ^
H:\Derivative quiz\derivativeQuiz.java:10: class, interface, or enum expected
    int question = Integer.parseInt(JOptionPane.showInputDialog(null, "Please enter the number of questions you wish to test on: "));
    ^
H:\Derivative quiz\derivativeQuiz.java:11: class, interface, or enum expected
    int numExp = Integer.parseInt(JOptionPane.showInputDialog(null, "Please enter the maximum exponent allowed (up to 5 supported):" ));
    ^
H:\Derivative quiz\derivativeQuiz.java:12: class, interface, or enum expected
    Random random = new Random();
    ^
H:\Derivative quiz\derivativeQuiz.java:13: class, interface, or enum expected
    int coeff;
    ^
H:\Derivative quiz\derivativeQuiz.java:14: class, interface, or enum expected
    String equation = "";
    ^
H:\Derivative quiz\derivativeQuiz.java:15: class, interface, or enum expected
    String deriv = "";
    ^
H:\Derivative quiz\derivativeQuiz.java:16: class, interface, or enum expected
    for(int z = 0; z <= question; z++)
    ^
H:\Derivative quiz\derivativeQuiz.java:16: class, interface, or enum expected
    for(int z = 0; z <= question; z++)
                   ^
H:\Derivative quiz\derivativeQuiz.java:16: class, interface, or enum expected
    for(int z = 0; z <= question; z++)
                                  ^
H:\Derivative quiz\derivativeQuiz.java:19: class, interface, or enum expected
        deriv = "";
        ^
H:\Derivative quiz\derivativeQuiz.java:20: class, interface, or enum expected
        if(numExp >= 5)
        ^
H:\Derivative quiz\derivativeQuiz.java:23: class, interface, or enum expected
            equation = coeff + "X^5 + ";
            ^
H:\Derivative quiz\derivativeQuiz.java:24: class, interface, or enum expected
            deriv = coeff*5 + "X^4 + ";
            ^
H:\Derivative quiz\derivativeQuiz.java:25: class, interface, or enum expected
        }
        ^
H:\Derivative quiz\derivativeQuiz.java:29: class, interface, or enum expected
            equation = equation + coeff + "X^4 + ";
            ^
H:\Derivative quiz\derivativeQuiz.java:30: class, interface, or enum expected
            deriv = deriv + coeff*4 + "X^3 + ";
            ^
H:\Derivative quiz\derivativeQuiz.java:31: class, interface, or enum expected
        }
        ^
H:\Derivative quiz\derivativeQuiz.java:35: class, interface, or enum expected
            equation = equation + coeff + "X^3 + ";
            ^
H:\Derivative quiz\derivativeQuiz.java:36: class, interface, or enum expected
            deriv = deriv + coeff*3 + "X^2 + ";
            ^
H:\Derivative quiz\derivativeQuiz.java:37: class, interface, or enum expected
        }
        ^
H:\Derivative quiz\derivativeQuiz.java:41: class, interface, or enum expected
            equation = equation + coeff + "X^2 + ";
            ^
H:\Derivative quiz\derivativeQuiz.java:42: class, interface, or enum expected
            deriv = deriv + coeff*2 + "X + ";
            ^
H:\Derivative quiz\derivativeQuiz.java:43: class, interface, or enum expected
        }
        ^
H:\Derivative quiz\derivativeQuiz.java:47: class, interface, or enum expected
            equation = equation + coeff + "X + ";
            ^
H:\Derivative quiz\derivativeQuiz.java:48: class, interface, or enum expected
            deriv = deriv + coeff;
            ^
H:\Derivative quiz\derivativeQuiz.java:49: class, interface, or enum expected
        }
        ^
H:\Derivative quiz\derivativeQuiz.java:53: class, interface, or enum expected
            equation = equation + coeff;
            ^
H:\Derivative quiz\derivativeQuiz.java:54: class, interface, or enum expected

            if(deriv == "")
            ^
H:\Derivative quiz\derivativeQuiz.java:57: class, interface, or enum expected
            }
            ^
H:\Derivative quiz\derivativeQuiz.java:114: class, interface, or enum expected
    JOptionPane.showMessageDialog(null, "Question " + z + "\\" + question + "\nDerivative: " + deriv);
    ^
H:\Derivative quiz\derivativeQuiz.java:115: class, interface, or enum expected
    }
    ^
33 errors

Process completed.

我觉得这是一个基本的错误，但我似乎找不到它。如果它有所作为，我正在使用JCreator进行编译，并且所有内容都已正确安装。

更新：我已经修复了所涉及的错误（类声明和不正确的导入语句（有人回去删除了几个分号））

工作代码：

import java.util.Random;
import javax.swing.JOptionPane;
import java.lang.String;
public class derivativeQuiz_source{
public static void main(String args[])
{
    //a bunch more code
}
}

感谢所有的帮助

答案 1

你错过了类声明。

public class DerivativeQuiz{
   public static void derivativeQuiz(String args[]){ ... }
}

答案 2

每个方法都应该在一个类中。您的方法在类之外。derivativeQuiz

public class ClassName {

 ///your methods
}