带变量的多种方法

Question

我需要第一个半径，但它无法识别，我该怎么做？顺便说一句，必须有两种方法，第二种方法必须使用第一种方法的半径。

    public static double areaCircle(double rad) {

        Scanner input = new Scanner(System.in);

        System.out.print("Enter radius : ");

        rad = input.nextDouble();

        double circ = Math.PI*Math.pow(rad, 2);

        return circ;

        }

    public static double volumeCylinder (double h) {


        Scanner input = new Scanner(System.in);

        System.out.print("Enter height : ");

        h = input.nextDouble();

        double cyl = Math.PI*Math.pow(rad, 2)*h;
    }

Answer 1

因为它没有获取有关该变量的信息。你必须传递价值

public static double areaCircle(double rad) {



    double circ = Math.PI*Math.pow(rad, 2);

    return circ;

    }

public static double volumeCylinder (double h, double rad) { //added double rad



    double cyl = Math.PI*Math.pow(rad, 2)*h;
}

当你从 main 调用它时

Scanner input = new Scanner(System.in);
 System.out.print("Enter radius : ");
rad = input.nextDouble();
System.out.print("Enter h: ");
h= input.nextDouble();
double something = volumeCylinder(h,rad);
double something = areaCircle(rad);