Question

我有以下代码，我正在尝试使用用户在if / else语句中输入的输入：

String userGuess = JOptionPane.showInputDialog("The first card is " 
    + firstCard + ". Will the next card be higher, lower or equal?");

如何使用他们输入的单词，即在此代码所在的if / else语句之外的“更高”，“更低”或“相等”？我需要他们答案的代码是：

if (userGuess == "higher" && nextCard > firstCard)
{
    String userGuess = JOptionPane.showInputDialog(null, "Correct! The current card is a " 
               + nextCard + ". Will the next card be higher, lower or equal?");
    correctGuesses++;
}

编辑：谢谢你的帮助，我明白了！

Answer 1

试试这段代码：

if (userGuess.equalsIgnoreCase("higher") && nextCard > firstCard)
{
    String userGuess = JOptionPane.showInputDialog(null, "Correct! The current card is a " 
           + nextCard + ". Will the next card be higher, lower or equal?");
    correctGuesses++;
}

else if (userGuess.equalsIgnoreCase("higher") && nextCard == firstCard)
{
    String userGuess = JOptionPane.showInputDialog(null, "Correct! The current card is a " 
               + nextCard + ". Will the next card be higher, lower or equal?");
    correctGuesses++;
}

else if (userGuess.equalsIgnoreCase("lower") && nextCard < firstCard)
{
    String userGuess = JOptionPane.showInputDialog(null, "Correct! The current card is a " 
               + nextCard + ". Will the next card be higher, lower or equal?");
    correctGuesses++;
}

String不是原始类型。您无法使用==代替：

if (userGuess.equalsIgnoreCase("higher") && nextCard > firstCard)
{

在字符串上查看Oracle的documentation。这应该会给你进一步的帮助。快乐的编码！

Answer 2

如果在if语句之外声明变量userGuess，并将其分配到内部，那么您将能够在if语句之外使用它。

另外，正如其他地方所述，你应该将字符串与equals（）进行比较，而不是==。

Answer 3

有两种不错的方式：

更改变量的名称（因此它不会与现有的userGuess变量冲突）并在if语句之外声明它。

String nextGuess = "";
if (userGuess.equals("higher") && nextCard > firstCard) {
    nextGuess = JOptionPane.showInputDialog(null, "Correct! The current card is a " + nextCard + ". Will the next card be higher, lower or equal?");
    correctGuesses++;
}

每次让用户输入内容时，只需使用相同的userGuess变量。

if (userGuess.equals("higher") && nextCard > firstCard) {
    userGuess = JOptionPane.showInputDialog(null, "Correct! The current card is a " + nextCard + ". Will the next card be higher, lower or equal?");
    correctGuesses++;
}

如何使用从Java中的字符串获取的输入？

3 个答案: