Java 程序在从 main() 拉出的变量之间输出空格，这很好。不过我想删除尾随空格

Question

这是我的代码:

    import java.util.Scanner;

    public class LabProgram {

    public static double drivingCost(double drivenMiles, double dollarsPerGallon, double milesPerGallon)
    {  double totalCost = 0;
    totalCost = (drivenMiles / milesPerGallon) * dollarsPerGallon ;
    System.out.printf("%.2f", totalCost);
    System.out.print(" ");
    return totalCost;
    }
    public static void main(String[] args) {
    Scanner input = new Scanner(System.in);
    double milesPGallon;
    double dollarsPGallon;
    double driveMiles;
    double drivingCost;
    milesPGallon = input.nextDouble();
    dollarsPGallon = input.nextDouble();
    input.close();
    drivingCost(10, dollarsPGallon, milesPGallon);
    drivingCost(50, dollarsPGallon, milesPGallon);
    drivingCost(400, dollarsPGallon, milesPGallon);
    System.out.print("\r");
    }
    }

输出是:“1.58 7.90 63.20”，我需要的是“1.58 7.90 63.20”。如何删除输出中的尾随空格？我尝试使用trim()和replace()都没有任何帮助。我是 Java 新手，在过去的一天半里我一直在用头撞墙试图解决这个问题。任何帮助将不胜感激，即使它只是朝着正确方向插入。先感谢您。

Answer 1

driveCost 每次调用时都会打印一个空格:

public static double drivingCost(double drivenMiles, double dollarsPerGallon, double milesPerGallon)
{
    double totalCost = 0;
    totalCost = (drivenMiles / milesPerGallon) * dollarsPerGallon ;
    System.out.printf("%.2f", totalCost);
    System.out.print(" "); // <-------- here!
    return totalCost;
}

您可以删除该行，并在对 driveCost 的调用之间打印一个空格:

drivingCost(10, dollarsPGallon, milesPGallon);
System.out.print(" ");
drivingCost(50, dollarsPGallon, milesPGallon);
System.out.print(" ");
drivingCost(400, dollarsPGallon, milesPGallon);

或者，向 driveCost 添加一个额外参数:

public static double drivingCost(double drivenMiles, double dollarsPerGallon, double milesPerGallon, boolean isLastCall)
{
    double totalCost = 0;
    totalCost = (drivenMiles / milesPerGallon) * dollarsPerGallon ;
    System.out.printf("%.2f", totalCost);

    if (!isLastCall) {
        System.out.print(" ");
    }
    return totalCost;
}

并这样调用它:

drivingCost(10, dollarsPGallon, milesPGallon, false);
drivingCost(50, dollarsPGallon, milesPGallon, false);
drivingCost(400, dollarsPGallon, milesPGallon, true);