[英]Java Compare single char to char array
我需要将单个char与char数组进行比较,看看array是否具有该char。
我当前的代码如下所示:
public boolean isThereChar(char[] chaArray, String chr){
boolean bool = false;
for(int i=0; i < chaArray.length; i++)
{
if(chr.equals(chaArray[i])){
bool = true;
}
}
return bool;
}
编辑注释:
真抱歉,造成混淆! 我只是Java初学者= /
基本上我是用GUI编写小型Hangman游戏。
我的程序读取了文本文件,并随机选择了玩家必须猜测的单词,然后以隐藏方式将其打印出来,如下所示:_ _ _ _ _
在这种情况下,我希望玩家输入字符或字符串(人们可以猜测整个单词或仅一个字母)
然后,我希望我的程序采用该字母或字符串并与隐藏的单词进行比较
以下代码选择单词并将其隐藏:
public String pickWord(){
String guessWord = (wordsList[new Random().nextInt(wordsList.length)]);
return guessWord.toLowerCase();
}
//Hides picked word
public char[] setWord(){
char[] word = new char[pickWord().length() * 2];
for (int i = 0; i < word.length; i+=2) {
word[i] = '_';
word[i + 1] = ' ';
}
return word;
}
然后人输入他想用以下代码编程的字符:
public void actionPerformed(ActionEvent e) {
String action = e.getActionCommand();
if (action == "Guess Letter"){
inputChar = JOptionPane.showInputDialog("Please enter letter (a-z)");
if (inputChar.length() > 1){
GuessedLetters glr = new GuessedLetters(inputChar);
glr.setInString(inputChar);
//For testing purposes
System.out.println("This is String: " +glr.getInString());
}else{
GuessedLetters glr = new GuessedLetters(inputChar);
glr.setInChar(inputChar);
//For testing purposes
System.out.println("This is Char: " +glr.getInChar());
}
}
最后,我要输入的字符与我隐藏的单词字符数组进行比较:
public boolean isThereChar(char[] array, String str){
return isThereChar(array, str.charAt(0));
}
public boolean isThereChar(char[] array, char c){
for(int i=0; i<array.length; i++){
if (array[i] == c) return true;
}
return false;
}
我想检查我的代码返回什么(对或错),但是我一直失败。 (现在,我正在尝试在主类中调用method进行检查,如果可以给我提示如何做的话,否则请告诉我。)
我将使用: Chars.contains(array, chr);
与番石榴糖
之所以发生NullPointerException,是因为调用该方法时chaArray
或chr
为null
。 ( 如果不是,则NullPointerException发生在其他地方! )
您的代码的另一个问题是这一行:
if (chr.equals(chaArray[i])) {
由于chr
实际上是一个String,因此这里将发生的是chaArray[i]
的值将自动装箱为Character
对象,然后作为参数传递给String.equals(Object)
。 但是,除非String.equals(Object)
的参数为String
否则它将返回false
,因此您的代码将始终找不到该字符。
您需要像这样比较字符:
if (chr.charAt(0) == chaArray[i]) {
或将chr
声明为char
并将其比较为:
if (chr == chaArray[i]) {
让我们看看我是否满足您的需求:
public void actionPerformed(ActionEvent e) {
String action = e.getActionCommand();
if (action == "Guess Letter"){
inputChar = JOptionPane.showInputDialog("Please enter letter (a-z)");
if (inputChar.length() > 1){ //User input is a string here, right?
GuessedLetters glr = new GuessedLetters(inputChar);
glr.setInString(inputChar);
System.out.println(wordToGuess.contains(glr.getInString())); //This will print true if wordToGuess is equal to glr.getInString() or if it just contains it
//For testing purposes
System.out.println("This is String: " +glr.getInString());
}else{ //Here the user gave us just a character, so we've got to know if this character is contained in the word, right?
GuessedLetters glr = new GuessedLetters(inputChar);
glr.setInChar(inputChar);
System.out.println(wordToGuess.contains(glr.getInChar()); //This will print true if your char is in the wordToGuess string
//For testing purposes
System.out.println("This is Char: " +glr.getInChar());
}
}
}
String chr
可能为null,从而导致NullPointerException
。
使用char chr
而不是String
。
public boolean isThereChar(char[] chaArray, char chr){
boolean bool = false;
for(int i=0; i < chaArray.length; i++) {
if(chr==chaArray[i])){
bool = true;
}
}
return bool;
}
从传入的参数中选择字符,或传入一个字符,例如
chr[0]
要么
public String isThereChar(char[] chaArray, char chr){
for(int i=0; i < chaArray.length; i++)
{
if(chr.equals(chaArray[i])){
return chr;
}
}
return "Guess Again";
}
public boolean isThereChar(char[] chaArray, char chr){
for(int i=0; i < chaArray.length; i++)
{
if((chaArray[i]==chr)){
return true; // means Character exist in the Character array
}
}
return false; //// means Character does not exist in the Character array
}
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