如何修复Java中表达错误的非法启动

Question

我得到错误：

表达非法的开始，没有if and If nif and nifegal声明开始。

这是代码：

import java.util.Scanner;
public class Temperature_Converter {
    public static void main(String[] args) {
        System.out.println("Welcome!This program takes temperature as an input and an input" +
                " indicating wether we're converting from Celsius to Fahrenheit or Fahrenheit to Celsius");
        Scanner scan = new Scanner (System.in);
                System.out.println("Please enter "C" if we're converting from Fahrenheit");
        System.out.println("Please enter "F" if we're converting from Celsius");
        String temp_key = scan.nextLine();
        System.out.println("Please enter the numerical value of the temperature");
        double temp_value = scan.nextDouble();
        if (temp_key.equals("F"));
        {
            {
                double result = temp_value - 32 / 1.8;
                System.out.println("When converting " + temp_value + "Fahrenheit to Celsius,n" +
                        " the result is " + result);
            }
             else if (temp_key.equals("C")
        }
             double result = temp_value * 1.8 + 32;
             System.out.println("When converting " + temp_value + "From Celsius to Fahrenheit,n + ");
                                "the result is;"+ result;);
    }
    static {;
    System.out.println("Next time make sure you enter either F or C");
    }
}

Answer 1

丢失半隆和双嵌套卷曲支撑块

这个：

    if (temp_key.equals("F"));
    {
        {
            double result = temp_value - 32 / 1.8;

应该是：

    if (temp_key.equals("F"))
    {
        double result = temp_value - 32 / 1.8;

我在这里...

此语句：

double result = temp_value - 32 / 1.8;

不像您认为的那样从F转换为C。32/1.8首先评估。(就像您在9年级代数中学到的一样(。你想说：

double result = (temp_value - 32) / 1.8;