Question

无论出于何种原因，我的变量＆＃39;小时＆＃39;仅存在为0.当我输入96作为距离，1作为小时，43作为分钟，我的答案是133.9英里每小时。它应该是55.9223。我为询问我确定的一个显而易见的问题而道歉，但我很早就学习了java。

import java.util.Scanner;
import static java.lang.System.*;
import static java.lang.Math.*;

public class mph
{
private double distance, hours, minutes;
private double mph;

public mph()
{
    setNums(0,0,0);
    mph=0.0;
}

public mph(double dist, double hrs, double mins)
{

    distance=dist;
    hours=hours;
    minutes=mins;
}

public void setNums(double dist, double hrs, double mins)
{
    dist=distance;
    hrs=hours;
    mins=minutes;



}

public void calcMPH()
{
    hours=minutes/60; //hours is not being input, it counts as zero regardless of what's entered
    mph=distance/hours;

}

public void print()
{
     System.out.print((int)distance+" miles in "+(int)hours+" hours and "+(int)minutes+" minutes = "+mph+" mph.\n");

}

}

-------------------单独的文件----------------

import java.util.Scanner;
import static java.lang.System.*;
import static java.lang.Math.*;

public class mphRunner
{
public static void main( String[] args )
{
    Scanner keyboard = new Scanner(in);

    out.print("Enter the distance :: ");
    double dist = keyboard.nextInt();

    out.print("Enter the hours :: ");
    double hrs = keyboard.nextInt();

    out.print("Enter the minutes :: ");
    double mins = keyboard.nextInt();

    mph test = new mph(dist, hrs, mins);
    test.calcMPH();
    test.print();

}
}

如果我以某种方式弄乱了正确的格式，我很抱歉，这是我在网站上的第一篇文章。编辑：哦，天哪，我是个白痴。

Answer 1

您要将变量hours分配给自己而不是参数hrs。变化

hours=hours;

到

hours=hrs;

Answer 2

这是您尝试的惯用版本：

Q33636764.java

import java.util.Scanner;

public class Q33636764
{
    private static int getData(final Scanner scanner, final String message)
    {
        System.out.print(message);
        if (scanner.hasNextInt()) { return scanner.nextInt(); }
        else
        {
            System.out.println("Please enter an Integer!");
            return getData(scanner, message);
        }
    }

    public static void main(final String[] args)
    {
        final Scanner keyboard = new Scanner(System.in);

        final int dist = getData(keyboard, "Enter the distance : ");
        final int hrs = getData(keyboard, "Enter the hours : ");
        final int mins = getData(keyboard, "Enter the minutes : ");

        final Mph mph = new Mph(dist, hrs, mins);
        System.out.format("%d miles in %d hours and %d minutes %.2f mph.", dist, hrs, mins, mph.calculate());
        System.out.println();
    }

    public static class Mph
    {
        private final double distance;
        private final double hours;
        private final double minutes;

        public Mph(final double distance, final double hours, final double minutes)
        {
            this.distance = distance;
            this.hours = hours;
            this.minutes = minutes;
        }

        public double calculate()
        {
            return this.distance / this.hours + this.minutes / 60;
        }
    }
}

输出：

Enter the distance : 100
Enter the hours : 1
Enter the minutes : 0
100 miles in 1 hours and 0 minutes 100.00 mph.

尽管扫描仪分配了不同的数字

2 个答案:

这是您尝试的惯用版本：

Q33636764.java

输出：