回文原来是这样的

import java.util.*;
public class HuiWen {
public static void main(String[] args) {
Scanner in = new Scanner(System.in);
System.out.println("please input a String:");
String st = in.nextLine();
String s = st.toLowerCase();
int i = 0;
int j = s.length() - 1;
boolean t = true;
char first = s.charAt(i);
char last = s.charAt(j);
for(;i<j;){
while(!(first >= 'a' && first <= 'z')){
i++;
first = s.charAt(i);
}
while(!(last >= 'a' && last <='z')){
j--;
last = s.charAt(j);
}
if(i >= j){
break;
}
if(first == last){
i++;
j--;
first = s.charAt(i);
last = s.charAt(j);
}
else{
t = false;
break;
}
}
if(t)
System.out.println(st + "是回文串");
else
System.out.println(st + "不是回文串");
}

}