java - 我在bluej中编译了一个switchcase程序来计算圆的一些参数。但我在编译过程中遇到了错误

Question

错误显示-“孤立案例”。但我已经尝试了很多次并检查了牙套。程序如下-

/**
 * Switch case program to calculate area, circumference, chord & area of segment of a circle 
 * with user interaction. User will be prompt to enter the radius and central angle of the circle.
 * The result will be calcuated based on the provided radius value and central angle value. 
 */
import static java.lang.Math.*;
public class CircleDemo
{
    public static void main(double ch, double x, double r)
    {
        /**
         * Here, x is the central angle of the circle and r is the radius of the circle
         */
        System.out.println("1. Area of the circle"+"/n"+"2. Length of the arc of the circle"+"/n"+"3. Length of the chord of the circle"+"/n"+"4. Area of the segment of the circle"+"/n"+"Enter your choice");
        Switch (ch); {
            case 1:double area= PI*pow(r,2);
                    System.out.println("Area of the circle="+area);
                    break;
            case 2:double arc= PI*r*(x/180);
                    System.out.println("Length of the arc of the circle="+arc);
                    break;
            case 3:double chord= 2*r*sin(x/2);
                    System.out.println("Length of the chord of the circle="+chord);
                    break;
            case 4:double segment= (((PI*pow(r,2)*x)/360)-((pow(r,2)*sin(x))/2));
                    System.out.println("Area of the segment of the circle="+segment);
                    break;
            default:System.out.println("Invalid choice");
        }
    }
}

Answer 1

1. 您无法打开 double 变量，因此请将 ch 更改为 int 或在 中将其强制转换为 int switch 语句。
2. 开关应为开关
3. 删除此处的; - switch (ch);