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我是新来的。我会感谢一些帮助，我正在努力编写一个程序来找到一个句子中的回文，这是我迄今为止所做的。然而，每当我执行它时，回文计数就会变为零，并且for和ifs中的System.out.println不会发生，我不明白什么是错误的。我们必须使用for循环，而不是while。如何检查句子中的回文数？
import java.util.Scanner;
class palcheck {
public void main() {
Scanner sc = new Scanner(System.in);
System.out.println("Enter the sentence please...");// input sentece
String s = sc.next();// the sentence
String wordback = ""; //reverse of a word of the sentence
int count = 0; // palindrome count
String word = "";// for a word of the sentence
int a; // counter
String s2 = null; //sentence but with removed full stop
if (s.charAt(s.length() - 1) == '.')// checking if ends with fullstop
{
s2 = s.substring(0, (s.length() - 1));
}// sentence without fullstop
System.out.println(s2);
String s3 = " " + s2 + " ";
System.out.println(s3);// added a space;
for (int c = 0; c < s3.length(); c++) {
char isspace = s3.charAt(c);
if (isspace == ' ')// checking
{
char x = ' ';// initilaizing
for (a = s3.indexOf(isspace); x != ' '; a++) {
x = s3.charAt(a); //collecting letters for word
word = word + x; // forming word
System.out.println("word is " + word);// the formed word
}
int l2 = word.length();
for (int i = l2 - 1; i >= 0; i--) {
wordback = wordback + word.charAt(i);// forming reverse word
System.out.println("reverse word is " + wordback);
if (word.equalsIgnoreCase(wordback)) {
count = count + 1;
}// increasing palindrome count
word = null;// resetting value
wordback = null;//resetting value
}
}
}
System.out.println("the no of palindromes is " + count);
}
}
编辑：我试图改变变量的名称：
import java.util.Scanner;
class palcheck {
public void main() {
Scanner sc = new Scanner(System.in);
System.out.println("Enter the sentence please...");// input sentece
String sentence = sc.next();// the sentence
String wordreverse = ""; //reverse of a word of the sentence
int count = 0; // palindrome count
String word = "";// for a word of the sentence
int a; // counter
String sentencewithoutfullstop = null; //sentence but with removed full stop
if (sentence.charAt(sentence.length() - 1) == '.')// checking if ends with fullstop
{
sentencewithoutfullstop = sentence.substring(0, (sentence.length() - 1));
}// sentence without fullstop
System.out.println(sentencewithoutfullstop);
String sentencewithspace = " " + sentencewithoutfullstop + " ";
System.out.println(sentencewithspace);// added a space;
for (int c = 0; c < sentencewithspace.length(); c++) {
char isspace = sentencewithspace.charAt(c);
if (isspace == ' ')// checking
{
char letter = ' ';// initilaizing
for (a = sentencewithspace.indexOf(isspace); letter != ' '; a++) {
letter = sentencewithspace.charAt(a); //collecting letters for word
word = word + letter; // forming word
System.out.println("word is " + word);// the formed word
}
int length2 = word.length();
for (int i = length2 - 1; i >= 0; i--) {
wordreverse = wordreverse + word.charAt(i);// forming reverse word
System.out.println("reverse word is " + wordreverse);
if (word.equalsIgnoreCase(wordreverse)) {
count = count + 1;
}// increasing palindrome count
word = null;// resetting value
wordreverse = null;//resetting value
}
}
}
System.out.println("the no of palindromes is " + count);
}
}
编辑：我重做的计划，但它没有得到执行。我正在使用bluej，并且每当我被选中void（main），java虚拟机都会继续运行，我必须终止它。
程序中有问题吗？
import java.util.Scanner;
class cal {
public static void main(String args[]) {
Scanner sc = new Scanner(System.in);
String input = sc.next();
String word = null;
String reverse = null;
int count = 0;
if (input.endsWith(".")) {
String Sent2 = input.substring(0, (input.length() - 1));
String sent3 = " " + Sent2 + " ";
int l = sent3.length();
for (int i = 0; i < l; i++) {
if (sent3.charAt(i) == ' ') {
while (sent3.charAt(i + 1) != ' ') {
char h = sent3.charAt(i + 1);
word = word + h;
int l2 = word.length();
for (int j = l2 - 1; j >= 0; j--) {
char hg = word.charAt(j);
reverse = reverse + hg;
if (word.equalsIgnoreCase(reverse)) {
System.out.println("palindrome :" + word);
count++;
}
}
}
}
}
} else {
String sent3 = " " + input + " ";
int l = sent3.length();
for (int i = 0; i < l; i++) {
if (sent3.charAt(i) == ' ') {
while (sent3.charAt(i + 1) != ' ') {
char h = sent3.charAt(i + 1);
word = word + h;
int l2 = word.length();
for (int j = l2 - 1; j >= 0; j--) {
char hg = word.charAt(j);
reverse = reverse + hg;
if (word.equalsIgnoreCase(reverse)) {
System.out.println("palindrome :" + word);
count++;
}
}
}
}
}
}
}
}
使用调试器，将您的代码划分为可理解和简短的方法...在发布您的问题之前需要做的事情还有很多。 – Idos
并提示：仔细查看格式正确的代码。这是比阅读更难以阅读的东西的10倍。并且：为你的变量使用更好的名字。 s1，s2，s3 ...对这些东西的内容说**没有任何**。最后：您可以使用String.split（“”）将句子分成几部分;你不必手动扫描空间字符！ – GhostCat
@GhostCat非常感谢你！我试图更好地命名变量并将其上传。但是，我们还没有在学校完成String.split功能，我不确定我们的老师是否会赞成，但是我会再试一次。谢谢！ –