java - 更改字符串中的某些字符

Question

我是一名初学者程序员，我正在尝试制作一个非常简单的 Hangman 版本。我的代码有很大问题。这是我遇到问题的代码部分:

        for(int i = 0; i <= wordLength - 1; i++ ) {

            if (letter == theWord.charAt( i )) {

                onemore=i+1;
                System.out.println("This letter matches with letter number " + onemore + " in the word.");
                ***displayWord.charAt(i)=letter;***
                System.out.println("The word so far is " + displayWord);
            } 

        }

我遇到错误的部分两侧各有 3 个星号。

displayWord 是一个字符串，而 letter 是一个字符。

Netbeans 告诉我:

unexpected type
  required: variable
  found:    value

我不知道问题是什么。

Answer 1

基本上，Java String 是不可变的，即内容无法更改。

您最好使用StringBuilder。

String theWord = "This is a simple test";
char letter = 'i';
char changeTo = '-';

StringBuilder displayWord = new StringBuilder(theWord);

int i = theWord.indexOf(letter);
if (i != -1) {
    System.out.println("This letter matches with letter number " + (i + 1) + " in the word.");
    displayWord.setCharAt(i, changeTo);

    System.out.println("The word so far is " + displayWord);
}

System.out.println(displayWord);

这会导致:

This letter matches with letter number 3 in the word.
The word so far is Th-s is a simple test
This letter matches with letter number 6 in the word.
The word so far is Th-s -s a simple test
This letter matches with letter number 12 in the word.
The word so far is Th-s -s a s-mple test
Th-s -s a s-mple test

现在简短的版本可能看起来像这样

String displayWord = theWord.repace(letter, changeTo);