java - 如何在 if 语句中使用键盘上的字符 [Java]

Question

我的代码有点问题。我需要将温度从摄氏度转换为华氏度，反之亦然，用户选择“F”或“C”(小写或大写)，但似乎无法弄清楚如何正确执行。我不知道如何让它识别该变量应该通过键盘输入。

 Scanner Keyboard = new Scanner(System.in); 
 System.out.println("Type C to convert from Fahrenheit to Celsius or" + 
        "F to convert from Celsius to Fahrenheit."); 
 char choice = Keyboard.nextLine().charAt(0);
 //Get user input on whether to do F to C or C to F 
 if (choice == F) //Fahrenheit to Celsius
 { 
      System.out.println("Please enter the temperature in Fahrenheit:"); 
      double C = Keyboard.nextDouble();
      double SaveC = C;
      C = (((C-32)*5)/9);
      System.out.println(SaveC + " degrees in Fahrenheit is equivalent to " + C + " degrees in Celsius."); 
 } 
 else if (choice == C) 
 { 
      System.out.println("Please enter the temperature in Celsius:"); 
      double F = Keyboard.nextDouble(); 
      double SaveF = F;
      F = (((F*9)/5)+32); 
      System.out.println(SaveF +" degrees in Celsius is equivalent to " + F + " degrees in Fahrenheit."); 
 } 
 else if (choice != C && choice != F) 
 { 
      System.out.println("You've entered an invalid character.");
 } 

Answer 1

您可以使用 Scanner 读取您的输入，然后调用查看它是否等于“C”或“F”

例如，

Scanner x = new Scanner(System.in);

String choice = x.nextLine();

if (choice.equals("F") || choice.equals("f")) { 
    blah blah blah
}
if (choice.equals("C") || choice.equals("c")) {
    blah blah blah 
}