需要帮助解决Square Class问题，特别是代码？

Question

我试图学习java，而我被卡在'类'部分。他们给了我一个问题，我不知道为什么这是错的。

我已经读了很多，我不明白为什么有大约14个错误信息？在所有...

这里的任务：

// You are to write the constructor specified for this Square class. The Square class 
    // has an instance variable of type double, side, which is the length of each side of 
    // the square. The javadoc has been provided for you to help you tell what you needs to 
    // be done 
// 
// HINT: Write the constructor for the class Square. 
// The constructor will take in a parameter of the type double 
// and assign that parameter to the instance variable side 

这里是我的代码：

public class Square(double side) 

    private double side; 

    /** 
    * Constructor for objects of class Square 
    * @param theSide the length of the side of this Square 
    */ 
    public main(double theSide) { 
    side = theSide; 
    } 
    /** 
    * Gets the length of a side of this square 
    * @return the side of this square 
    */ 
    public double getSide() 
    { 
    return side; 
    } 


Compiler error: /tmp/codecheck.XNhW00Z3c8/Square.java:12: error: '{' expected public class Square(double side)^/tmp/codecheck.XNhW00Z3c8/Square.java:12: error: ';' expected public class Square(double side)^/tmp/codecheck.XNhW00Z3c8/Square.java:31: error: reached end of file while parsing }^/tmp/codecheck.XNhW00Z3c8/Square.java:14: error: variable side is already defined in class Square private double side;^

Answer 1

你实际上是在给参数类。在Java类中不应该有一个参数

这里看看

public class Square(double side) 

正道类

public class Square 
{ 
    private double side; 
    public Square(double theSide) 
    { 
     side=theSide; 
    } 
    public double getSide() 
    { 
     return side; 
    } 


} 

另一个类

public class TestSquare 
{ 

    public static void main(String[] args) 
    { 
     Square square = new Square(25.00); 
     System.out.println("Square sides:"+square.getSide()); 
    } 
}