所以我正在做一个回文检查器,它的作用是通过一个语句,例如说“ racecar”,如果它是一个回文,它将说是正确的,在这种情况下是因为向后的赛车是赛车,但如果输入的是“ ratecar”,那么它将说为false,因为ratecar与racetar不同,并且我不断收到错误,例如字符串索引超出错误的范围类型。我创建了一个新页面,并尝试仅使用此页面:
class Main
{
public static void main(String[] args)
{
String str = new String("Go Hang A Salami, I'm a Lasagna Hog!");
str = str.toLowerCase();
str = str.replaceAll(" ","");
str = str.replaceAll("[^a-zA-Z ]","");
System.out.println(str);
}
}
并且它执行所需的操作并提供输出:“ gohangasalamiimalasagnahog”但是当我合并上面的内容时,下面显示的我创建的检查程序无法正常工作。
class Main
{
public static void main(String[] args)
{
System.out.println("This is A-A-Ron's palindrome checker");
System.out.println(isPalindrome("Go Hang A Salami, I'm A Lasagna Hog!"));
}
public static boolean isPalindrome(String str)
{
int len = str.length();
int i, j;
j = len - 1;
for (i = 0; i <= (len - 1)/2; i++)
{
str = str.toLowerCase();
str = str.replaceAll(" ","");
str = str.replaceAll("[^a-zA-Z ]","");
System.out.println(str);
if(str.charAt(i) != str.charAt(j))
{
return false;
}
j--;
}
System.out.println(str);
return true;
}
`````
It should give the output of:
"This is A-A-Ron's palindrome checker
gohangasalamiimalasagnahog
true"
But, it is giving me this:
"This is A-A-Ron's palindrome checker
gohangasalamiimalasagnahog
Exception in thread "main" java.lang.StringIndexOutOfBoundsException: String index out of range: 35
at java.lang.String.charAt(String.java:658)
at Main.isPalindrome(Main.java:28)
at Main.main(Main.java:9)
exit status 1"
What do I do to fix it?
您的问题非常简单。您从原始字符串中获得了len
,但是在循环中替换了一些字符串。就这样吧
public static boolean isPalindrome(String str) {
str = str.toLowerCase();
str = str.replaceAll(" ", "");
str = str.replaceAll("[^a-zA-Z ]", "");
System.out.println(str);
int len = str.length();
int i, j;
j = len - 1;
for (i = 0; i <= (len - 1) / 2; i++) {
if (str.charAt(i) != str.charAt(j)) {
return false;
}
j--;
}
System.out.println(str);
return true;
}
您正在存储原始字符串(36)的长度,然后从中删除空白并尝试访问该索引,但是新字符串较短,会出现错误。