摄氏度/华氏度转换误差

Question

很抱歉我的初学者错误，但我正在编写一个计算器，可以将华氏度转换为摄氏度，将摄氏度转换为华氏度，但我不断收到此错误：

Exception in thread "main" java.lang.NumberFormatException: 
For input string: "69C"
    at sun.misc.FloatingDecimal.readJavaFormatString(FloatingDecimal.java:1241)
    at java.lang.Double.valueOf(Double.java:504)
    at Converter.main(Converter.java:39)  

这是我的代码，希望你能帮到：

import java.util.Scanner; 
public class Converter {
    public static void main(String[] args) {
        Scanner keyboard = new Scanner(System.in);
        System.out.println("Welcome to the Fahrenheit/Celsius Converter!");
        System.out.println("To convert, type in your temperature and the
                            identify if you are using fahrenheit or celsius.");
        System.out.println("Example: 69F or 69C F = Fahrenheit C = Celsius");
        String temperature;
        char f = 'f';
        char c = 'c';
        double answer , temp;
        temperature = keyboard.nextLine();            
        if (temperature.contains("F")) {
            temperature = temperature.replace(f , ' ');
            temp = Double.valueOf(temperature);
            answer = temp - 30 / 2;
            System.out.println("Poof! The temperature is " + answer + "C");
        } else {
            System.out.println("You entered the temperature wrong!");
        }
        if (temperature.contains("F")) {
            temperature = temperature.replace(f , ' ');
            temp = Double.valueOf(temperature);
            answer = temp - 30 / 2;
            System.out.println("Poof! The temperature is " + answer + "C");
        } else {
            System.out.println("You entered the temperature wrong!");
        }
        if (temperature.contains("C")) {
            temperature = temperature.replace(c , ' ');
            temp = Double.valueOf(temperature);
            answer = temp + 30 * 2;
            System.out.println("Poof! The temperature is " + answer + "F");
        } else {
            System.out.println("You entered the temperature wrong!");
        }
        if (temperature.contains("c")) {
            temperature = temperature.replace(c , ' ');
            temp = Double.valueOf(temperature);
            answer = temp + 30 * 2;
            System.out.println("Poof! The temperature is " + answer + "F");
        } else {
            System.out.println("You entered the temperature wrong!");
        }
    }
}

Answer 1

你不能将69C转换为一个数字，可以吗？ 替换区分大小写

尝试

temperature = temperature.replace('C' , ' ');

当然，您可以将变量更改为"C"

Answer 2

该错误告诉您需要知道的所有内容 - 直到行号！"69C"不是整数，所以当你尝试解析它时，它不起作用！