方法和传递一个双

Question

我不断收到有关这段代码的错误消息。我尝试声明它并以不同的方式传递它。如果代码不是那么先进，我很抱歉。我还是个初学者。

/*
 * To change this template, choose Tools | Templates
 * and open the template in the editor.
 */

package javaapplication5;
import java.util.Scanner;

/**
 *
 * @author period3
 */
public class JavaApplication5 {

/**
 * @param args the command line arguments
 */


public static void main(String[] args) {


    double theresult;
    theresult = area(double radius);

Scanner reader;
reader = new Scanner (System.in);
System.out.println("Please enter the coordinates of a circle:");
newLine();
System.out.println("Outside point:");
newLine();
System.out.println("x1:");
int x1 = reader.nextInt();
newLine();
System.out.println("y1:");
int y1 = reader.nextInt();
newLine();
System.out.println("Center Point:");
newLine();
System.out.println("x2:");
int x2 = reader.nextInt();
newLine();
System.out.println("y2:");
int y2 = reader.nextInt();

System.out.println("The area of the circle is" + theresult);

}
 public static double distance(int x1, int y1, int x2, int y2) 
{
double dx = x2 - x1;
double dy = y2 - y1;
double dsquared = dx*dx + dy*dy;
double result = Math.sqrt (dsquared);
return result;
}

public static double area(int x1, int y1, int x2, int y2) {
double radius = distance (x1, y1, x2, y2);
return radius;
}

public static double area(double radius)
{
    double areaCircle;
    areaCircle = (3.14 * (radius * radius));
    return areaCircle;
}


//NewLine Method
public static void newLine () {
System.out.println ("");
}
}

以及我在第 24 行的错误信息（theresult = area(double radius):

unexpected type
  required: value
  found:    class

'.class' expected

';' expected
----

Answer 1

在使用面积法之前需要先计算半径：

double radius = distance(x1, y1, x2, y2);

那你需要设置结果：

theResult = area(radius);

这些都应该发生在您的用户输入之后（在他们为您提供 x1、y1、x2 和 y2 的值之后，以及 在您打印 theResult 之前.

请注意我如何称呼您的 distance 和 area 方法。只需将局部变量输入参数即可。

theResult = area(double radius); <- This is incorrect syntax.