Question

我知道你们不在这里为我做功课，但我似乎无法让这个工作。我在类MPhRunner中收到一个错误，指出类MilesPerHour中的构造函数不能应用于给定的类型。我想我只是不明白这意味着什么。

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 :: ");
        int dist = keyboard.nextInt();

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

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

        MilesPerHour test = new MilesPerHour();
        test.setNums(dist, hrs, mins);
        test.calcMPH();
        test.print();
        }
}


import java.util.Scanner; 
import static java.lang.System.*;
import static java.lang.Math.*;
public class MilesPerHour
{
    private int distance, hours, minutes;
    private double mph;
    MPHRunner one= new MPHRunner();

    public MilesPerHour(int dist ,int hrs,int mins)
    {
        setNums(dist,hrs,mins);
        mph=0.0;
    }
    public void setNums(int dist, int hrs, int  mins)
    {
        minutes=mins;
        hours=hrs;
        distance=dist;
    }


    public void calcMPH()
    {
        mph= distance /(hours*60+minutes)/60;
    }

    public void print()
    {System.out.print("Your speed is"+mph);
    }
}

Answer 1

你的MilesPerHour构造函数有3个参数......你没有给它！试试：

MilesPerHour test = new MilesPerHour(dist, hrs, mins);

...并删除以下行（因为构造函数已经这样做了，所以它是多余的）：

test.setNums(dist, hrs, mins);

Answer 2

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 :: ");
        int dist = keyboard.nextInt();

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

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

        MilesPerHour test = new MilesPerHour(dist, hrs, mins);
        test.setNums(dist, hrs, mins);
        test.calcMPH();
        test.print();
        }
}

 class MilesPerHour
{
    private int distance, hours, minutes;
    private double mph;
    MPHRunner one= new MPHRunner();

    public MilesPerHour(int dist ,int hrs,int mins)
    {
        setNums(dist,hrs,mins);
        mph=0.0;
    }
    public void setNums(int dist, int hrs, int  mins)
    {
        minutes=mins;
        hours=hrs;
        distance=dist;
    }


    public void calcMPH()
    {
        mph= distance /(hours*60+minutes)/60;
    }

    public void print()
    {System.out.print("Your speed is"+mph);
    }
}

我修改了你的代码并且工作正常。希望这会对你有帮助。

Answer 3

构造函数与类具有相同的名称。

类MilesPerHour

public MilesPerHour＆lt; - constructor

对于方法，您也可以创建带参数的构造函数。

喜欢

public MilesPerHour（int dist，int hrs，int mins）

如果您想使用MilesPerHour，请使用MilesPerHour milePerHour = new MilesPerHour(dis, hrs, mins);

需要一些帮助来解决此任务

3 个答案: