Thousand Separator
给一个数字n, 返回加千位点号的n的字符串.
class Solution {
public String thousandSeparator(int n) {
StringBuilder sb = new StringBuilder();
StringBuilder t = new StringBuilder(n+"");
String s = t.reverse().toString();
for(int i = 0 ; i < s.length(); i++) {
if(i != 0 && i % 3 == 0)
sb.append(".");
sb.append(s.charAt(i));
}
return sb.reverse().toString();
}
}