java - 在java中显示2位输出小数

Question

我试图找出为什么输出小数时的 %.2f 声明在我的代码中不起作用，我检查了其他类似的问题，但我似乎找不到我收到的特定逻辑错误中的问题。当我去编译我的程序时，它编译得很好，我去运行它，一切输出都很好，直到我达到最终成本，我试图只显示带有两位小数的十进制值。

我在线程“main”中遇到异常

Java.util.illegalformatconversionexception  f! = Java.lang.string
At java.util.Formatter$formatspecifier.failconversion(Unknown Source)
At java.util.Formatter$formatspecifier.printFloat(Unknown Source)
At java.util.Formatter.format(Unknown Source)
At java.io.printstream.format(Unknown Source)
At java.io.printstream.printf(Unknown Source)
At Cars.main(Cars.java:27)

这是我的代码:

import java.util.Scanner;
public class Cars
{

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

    int carYear, currentYear, carAge;

    double costOfCar, salesTaxRate;
    double totalCost;

    String carModel;
    System.out.println("Please enter your favorite car model.");
        carModel = input.nextLine();
    System.out.println("Please enter the  year of the car");
        carYear = input.nextInt();
    System.out.println("Please enter the current year.");
        currentYear = input.nextInt();
        carAge = currentYear - carYear;
    System.out.println("How much does the car cost?");
        costOfCar = input.nextDouble();
    System.out.println("What is the sales tax rate?");
        salesTaxRate = input.nextDouble();
        totalCost = (costOfCar + (costOfCar * salesTaxRate));
    System.out.printf("The model of your favorite car is" + carModel + ", the car is" + " " + carAge + " " + " years old, the total of the car is" + " " + "%.2f",totalCost + " " + " dollars."); 

    }
}

我不太确定是什么原因导致了这个问题。

Answer 1

尝试:

System.out.printf("The model of your favorite car is %s, the car is %d years old, the total of the car is %.2f dollars.", carModel, carAge, totalCost);

或者更具可读性:

System.out.printf("The model of your favorite car is %s," +
                  " the car is %d years old," +
                  " the total of the car is %.2f dollars.",
                  carModel, carAge, totalCost);