java - 调试模块中的逻辑错误

Question

我在完成书中的作业时遇到问题。我正在编写一个 super 简单的应用程序，将华氏温度转换为摄氏度，反之亦然。一切工作都很完美，除了我编写的用于将华氏度转换为摄氏度的模块不断返回零。我无法弄清楚，我一直在 Eclipse 中进行调试，单步执行每个步骤，但我无法弄清楚我的 f>c 转换方程出了什么问题，或者可能还有什么问题。有比我更有经验的人能看到这个问题吗？我真的很感激您检查一下。非常感谢!

import java.util.Scanner;

public class TemperatureConversions 
{

    public static void main(String[] args) 
    {
        Scanner input = new Scanner(System.in);
        String initialType;
        double fahrenheit = 1;
        double celcius = 1;
        System.out.print("Would you like to enter a fahrenheit or celcius temperature for conversion? (f/c):  ");
        initialType = input.next();
        switch ( initialType )
        {
            case "f":
                System.out.printf("Please input fahrenheit temperature:  ");
                fahrenheit = input.nextDouble();
                celcius = celcius (fahrenheit);
                System.out.print("\n" + fahrenheit + "f converted to celcius is " +celcius + "c");
                break;
            case "c":
                System.out.printf("Please input celcius temperature:  ");
                celcius = input.nextInt();
                fahrenheit = fahrenheit (celcius);
                System.out.print("\n" + celcius + "c converted to fahrenheit is " + fahrenheit + "f");
                break;
            default:
                System.out.printf("%s is an invalid input.  Please try again, and only input either 'f' or 'c'");
                break;
        }
        System.out.printf("\nAdios Turd Nuggets");
    }

    public static double celcius(double f)
    {
        double c = 5 / 9 * (f - 32);
        return c;
    }

    public static double fahrenheit(double c)
    {
        double f = c * 1.8 + 32;
        return f;
    }
}

Answer 1

我认为问题出在表达式 5/9 上。如果将两个整数相除，结果也是整数，在本例中为 0。尝试 5.0/9.0 * (f - 32)