Java温度转换器错误

Question

我编写了这个程序，但不知道出了什么问题，基本上它是 C->F、F->C、C->K、K->C、F->K、K 的转换器->F。顺便说一句，这是我在这个网站上的第一个问题，我使用 Bluej。当我尝试转换它时，我得到一个错误的答案，但我的公式都是正确的(在谷歌上检查)...

/**
 * Program to 
 * 
 * Anirudh Gupta
 * th August 2014
 */
import java.io.*;
public class Temperature
{
   public static void main () throws IOException
   {
       InputStreamReader isr=new InputStreamReader(System.in);
       BufferedReader br=new BufferedReader(isr);
       System.out.println("Enter choice of scale in which current temperature in:");
       System.out.println(" 1)Celsius");
       System.out.println(" 2)Fahrenheit");
       System.out.println(" 3)Kelvin");
       int no=Integer.parseInt(br.readLine());
       double ans;
       switch(no)
       {
           case 1:
                System.out.println("Enter temperature to convert(in °C)");
                double C=Double.parseDouble(br.readLine());
                System.out.println("Enter choice of scale to which current temperature should be converted");
                System.out.println("1)Fahrenheit");
                System.out.println("2)Kelvin");
                int no1=Integer.parseInt(br.readLine());
                switch(no1)
                {
                    case 1:
                           ans=((9*C)/5)+32;
                           System.out.println(ans+"°F");
                           break;
                    case 2:
                           ans=C+273;
                           System.out.println(ans+"K");
                           break;
                }
                break;
           case 2:
                System.out.println("Enter temperature to convert(in °F)");
                double F=Double.parseDouble(br.readLine());
                System.out.println("Enter choice of scale to which current temperature should be converted");
                System.out.println("1)Celsius");
                System.out.println("2)Kelvin");
                int no2=Integer.parseInt(br.readLine());
                switch(no2)
                {
                    case 1:
                           ans=((5*(F-32))/9);
                           System.out.println(ans+"°C");
                           break;
                    case 2:
                           ans=((5/9)*(F-32))+273;
                           System.out.println(ans+"K");
                           break;
                }
                break;
           case 3:
                System.out.println("Enter temperature to convert(in K)");
                double K=Double.parseDouble(br.readLine());
                System.out.println("Enter choice of scale to which current temperature should be converted");
                System.out.println("1)Celsius");
                System.out.println("2)Fahrenheit");
                int no3=Integer.parseInt(br.readLine());
                switch(no3)
                {
                    case 1:
                           ans=K-273;
                           System.out.println(ans+"°C");
                           break;
                    case 2:
                           ans=((9/5)*(K-273))+32;
                           System.out.println(ans+"°F");
                           break;
                }
                break;
       }

   }
}

Answer 1

当您在整数算术中中执行该计算时，

(5/9) 的计算结果将为零。

同样，(9/5) 的计算结果为 1。

重写为5.0/9等，以便计算以浮点形式进行。