Question

我编写了一个简单的程序，以风速（km / h）为单位将其转换为Knots或Beaufort，并指出风是欧洲风暴或平静。起始速度需要输入主类，但我不能将其转移到第二类。此外，我很难从主要方法调用第二类方法。

我的主要课程：

import java.util.Scanner;

public class WindSpeedTester {
    public static void main(String[] args){
        System.out.println("Enter speed in km/hr.");
        Scanner kb = new Scanner(System.in);
        Double input = kb.nextDouble();

        WindStorm windSpeed = new WindStorm();

        System.out.println("What would you want wind speed in?");
        System.out.println("Enter 1 for km/hr, 2 for Beaufort, 3 for Knots, or 4 to exit.");

        int count = kb.nextInt();

        if (count < 0){
            while (count <0)
                System.out.println("Invalid input . Please enter a valid integer.");
                count = kb.nextInt();}
        else{
            while (count != 4 ){
                if (count == 1){
                    windSpeed.getKilometerPerHour(kilometersPerHour);}
                else if (count == 2){
                    windSpeed.getBeaufort(kilometersPerHour);}
                else if (count == 3){
                    windSpeed.getKnots(kilometersPerHour);}
                else if (count == 4){
                    System.out.println("Bye.");
                    System.exit(0);}
                else{
                    System.out.print("Invalid input.");}
        }
    }
    windSpeed.isCalm(kilometersPerHour);
    windSpeed.isOrcan(kilometersPerHour);
    kb.close();
    }
}

WindStorm上课：

import java.util.Scanner;
public class WindStorm {

/**
 * the wind speed in kilometer per hour
 */
private double kilometerPerHour = 0.0;

public double windSpeed(double kilometerPerHour){
    double windSpeed = kilometerPerHour + input; //input is in main
    Scanner kb = new Scanner(System.in);
    while (windSpeed < 0){
        System.out.println("The wind speed entered is invalid. Enter another speed.");
        windSpeed = kb.nextDouble();}
    kb.close(); 
    return windSpeed;
}


/**
 * Return true if this wind speed is a
 * European windstorm (Orcan, more than
 * 120 km/h).
 */
public boolean isOrcan(double kilometersPerHour) {
    boolean isOrcan = true;
    if (kilometersPerHour > 120)
        System.out.println("The wind speed is Orcan.");
    return isOrcan; 
}
/**
 * Return true if this wind speed is
 * calm (less than 2 km/h).
 */
public boolean isCalm(double kilometersPerHour) {
    boolean isCalm = true;
    if (kilometersPerHour < 2)
        System.out.println("The wind is calm.");
    return isCalm;
}
public double getKilometerPerHour(double kilometersPerHour) {
    double getKilometerPerHour = kilometersPerHour; 
    System.out.println("The wind speed is: " + kilometersPerHour + " km/h.");
    return getKilometerPerHour;
}
/**
 * Returns the wind speed measured in knots (nautic miles).
 * A nautic mile is 1.852 kilometer.
 */
public double getKnots(double kilometersPerHour) {
    double getKnots = kilometersPerHour / 1852;
    System.out.println("The wind speed is: " + getKnots + "Knots (nautical miles).");
    return getKnots;
}
/**
 * Returns the wind speed measured in Beaufort (int 1-12).
 */
public int getBeaufort(double kilometersPerHour) {
    int getBeaufort = (int) Math.pow((kilometersPerHour / 3.01), (2/3));
    getBeaufort = (int) (getBeaufort + 0.5);            
        if (getBeaufort > 12)
            System.out.println("Invalid measurement.");
        else if (getBeaufort <= 0)
            System.out.println("Invalid measurement.");
        else
            System.out.println("The wind speed is: " + getBeaufort + "Knots.");
    return getBeaufort;
}
}

运行此代码，我收到以下错误：

Exception in thread "main" java.util.NoSuchElementException
at java.util.Scanner.throwFor(Scanner.java:907) 
at java.util.Scanner.next(Scanner.java:1530) 
at java.util.Scanner.nextDouble(Scanner.java:2456) 
at WindStorm.kilometersPerHour(WindStorm.java:15) 
at WindStorm.isOrcan(WindStorm.java:29) 
at WindSpeedTester.main(WindSpeedTester.java:26)

如何从其他类调用带有local参数的方法

0 个答案: