java - JAVA if语句逻辑或语法错误？

This question already has answers here:

How do I compare strings in Java?

（23个答案）


6年前关闭。





每次运行此程序时，我都会得到错误的结果，我觉得凌晨4点多睁一双眼睛会有所帮助。有人可以帮我找到大括号或括号的位置吗，因为我一生都找不到。

System.out.println("Please enter your guess") ;
    userGuess = kbd.next() ;
    if( userGuess != "a" || userGuess != "b" || userGuess != "c" ||
        userGuess != "d" || userGuess != "e" || userGuess != "f" || userGuess != "g" ||
        userGuess != "h" || userGuess != "i" || userGuess != "j" || userGuess != "k" ||
        userGuess != "l" || userGuess != "m" || userGuess != "n" || userGuess != "o" ||
        userGuess != "p" || userGuess != "q" || userGuess != "r" || userGuess != "s" ||
        userGuess != "t" || userGuess != "u" || userGuess != "v" || userGuess != "w" ||
        userGuess != "x" || userGuess != "y" || userGuess != "z" ||  userGuess!= "A" ||
        userGuess != "B" || userGuess != "C" || userGuess != "D" || userGuess != "E" ||
        userGuess != "F" || userGuess != "G" ||userGuess  != "H" || userGuess != "I" ||
        userGuess != "J" || userGuess != "K" ||userGuess  != "L" || userGuess != "M" ||
        userGuess != "N" || userGuess != "O" || userGuess != "P" || userGuess != "Q" ||
        userGuess != "R" || userGuess != "S" || userGuess != "T" || userGuess != "U" ||
        userGuess != "V" || userGuess != "W" || userGuess != "X" || userGuess != "Y" ||
        userGuess != "Z" ) {
        System.out.println("Invalid character, please enter your guess") ;
    }userGuess = kbd.next() ;

最佳答案

您需要将==更改为equals以比较String（和任何其他对象）的值。

同样，您在逻辑上也有问题，因为对于所有字符userGuess != "a" || userGuess != "b"都是正确的，因为如果某项是a则不是b，因此这些条件之一将始终为真。

您可能需要将||更改为&&或使用适当的工具（例如正则表达式）或Character类中的方法（例如Character.isLetter）。