java - 错误消息: "identifier expected"

Question

我正在做学习书“Java，如何编程”中的练习。我应该编写一个程序，让用户输入行驶里程以及未确定的出行次数所使用的汽油升数。

该程序应该打印每次行程的英里/升，并在最后打印平均英里/升。

我应该使用哨兵控制的重复，并将英里 pr 升打印为浮点值。

当我尝试编译时，我不断收到错误消息:

GasolineUsage.java:39: expected milPrLiter = (double) totalMil / totalLiters; ^ GasolineUsage.java:40: expected System.out.printf( "The car drives %.2f miles pr liter gasoline\n\n", milPrLiter );
^ GasolineUsage.java:40: illegal start of type System.out.printf( "The car drives %.2f miles pr liter gasoline\n\n", milPrLiter );
^ GasolineUsage.java:40: expected System.out.printf( "The car drives %.2f miles pr liter gasoline\n\n", milPrLiter );

^ GasolineUsage.java:42: class, interface, or enum expected } ^ 5 errors

代码如下:

import java.util.Scanner;
public class GasolineUsage
{

    public static void main( String[] args )
    {    
        int totalMil = 0;
        int totalLiters = 0;
        double milPrLiter1 = 0;
        double milPrLiter;

        Scanner inputMil = new Scanner(System.in);
        Scanner inputLiters = new Scanner( System.in);

        System.out.print( "Type in miles first trip, to end type: -1 " );
            int mil = inputMil.nextInt();
        System.out.print( "Type in liters of gasoline used on first trip " );
            int liters = inputLiters.nextInt();
            totalMil = totalMil + mil; 
            totalLiters = totalLiters + liters;
        milPrLiter1 = (double) mil / liters;
        System.out.printf( "(%.2f miles pr liter this trip.)\n", milPrLiter1 );

        System.out.print( "Type in miles on next trip " );
            while (mil != -1)
                {
                 mil = inputMil.nextInt();
                     if (mil != -1)
                         {totalMil = totalMil+ mil;

                         System.out.print( "Type in lters used on next trip: " );
                         liters = inputLiters.nextInt();}
                         totalLiters = totalLiters + liters;

                         milPrLiter1 = (double) mil / liters;
                         System.out.printf( "(%.2f miles pr liter this trip.)\n", milPrLiter1 );}
                 }

               milPrLiter = (double) totalMil / totalLiters;
               System.out.printf( "The car drives %.2f miles pr liter gasoline\n\n", milPrLiter );               
    }
} 

有人可以帮我吗？

Answer 1

计算您的左大括号和右大括号，因为它们应该匹配。您的代码中隐藏了一个额外的右大括号，如果您搜索它，您就会发现它。请注意，对于这种类型的错误，最好查看引发错误的行上方。