为什么我的代码不能编译？
我想弄清楚为什么这段代码没有正确编译。 当我尝试编译时，我得到它需要一个主要的错误，当我添加main时，它会导致更多的错误，我真的不知道如何解决。 有人可以看看代码并帮助我吗？ 如果有人可以帮助它，将不胜感激。
public class Polygon {
private int numSides; //number of sides
private double sideLength; //length of each side
private double xCoord; //x-coordinate of th center of the polygon
private double yCoord;//the y-coordinate
private double apothem;//defines the apothem
private double perimeter;
/**
* no argument constructor
*/
public Polygon() {
this.numSides = 4;
this.sideLength = 10.0;
this.xCoord = 0.0;
this.yCoord = 0.0;
this.apothem = 5.0;
this.perimeter = 20.0;
}
/**
* constructor that takes arguments
*
* @param _numSides :-number of sides
* @param _sideLength :-the length of each side
* @param _xCoord :-the x coordinate
* @param _yCoord :-the Y coordinate
* @param _apothem :-the apothem
*/
public Polygon(int _numSides, double _sideLength, double _xCoord, double _yCoord, double _apothem) {
this.numSides = _numSides;
this.sideLength = _sideLength;
this.xCoord = _xCoord;
this.yCoord = _yCoord;
this.apothem = _apothem;
}
/**
*
* @return area of the polygon[double]
*/
public double getArea() {
perimeter = numSides * sideLength;
double area = (0.5) * apothem * perimeter;
return area;
}
//getter & setters
public int getNumSides() {
return numSides;
}
public void setNumSides(int numSides) {
this.numSides = numSides;
}
public double getSideLength() {
return sideLength;
}
public void setSideLength(double sideLength) {
this.sideLength = sideLength;
}
public double getxCoord() {
return xCoord;
}
public void setxCoord(double xCoord) {
this.xCoord = xCoord;
}
public double getyCoord() {
return yCoord;
}
public void setyCoord(double yCoord) {
this.yCoord = yCoord;
}
public double getApothem() {
return apothem;
}
public void setApothem(double apothem) {
this.apothem = apothem;
}
public double getPerimeter() {
return perimeter;
}
public void setPerimeter(double perimeter) {
this.perimeter = perimeter;
}
//to string method
@Override
public String toString() {
return "Polygon definitions[" + "number of sides=" + numSides + ", Each side length=" + sideLength + ", xCoord=" + xCoord + ", yCoord=" + yCoord + ", apothem=" + apothem + ']';
}
}
我很抱歉未事先包括错误。 当通过cmd编译时，我得到以下错误。
错误：在类Polygon中找不到Main方法，请将主方法定义为：public static void main（String [] args）或者JavaFX应用程序类必须扩展javafx.application.Application
在同一个包中创建一个名为Main的单独类。 在那里添加主要方法。 然后实例化一个对象。
public class Main {
public static void main(String[] args) {
Polygon p = new Polygon();
double apothem = p.getApothem();
System.out.println(apothem);
}
}
你的代码编译得很好。 你所缺乏的是另一个使用你刚创建的对象类的类。
所以基本上你需要做的是去你的编辑器（eclipse，notepad ++等），创建另一个文件并使用如下所示：
public class PolygonMain {
public static void main(String[] args) {
Polygon p = new Polygon();
Here you can use your getters/setters toString etc.
The name of the object you've created in this example would be p, therefore
p.toString() would return the toString method of your object class
}
}