nyoj-1092-数字分隔（二）

java大法好啊
思路:单独拿出整数部分分隔
 1 import java.math.BigDecimal;
 2 import java.util.Scanner;
 3 
 4 public class Main{
 5 
 6     public static void main(String[] args) {
 7         Scanner cin = new Scanner(System.in);
 8         while (cin.hasNext()) {
 9             BigDecimal num = new BigDecimal("0");
10             num = cin.nextBigDecimal();
11             
12             // 判断负数
13             boolean flag = true;
14             if (num.compareTo(BigDecimal.valueOf(0)) < 0) {
15                 flag = false;
16                 num = num.abs();
17             }
18             num = num.setScale(2, BigDecimal.ROUND_HALF_UP);
19             // 保留小数部分
20             String str = num.toString();
21             String tail = str.substring(str.indexOf("."), str.length());
22 
23             // 保留头部
24             StringBuffer head = new StringBuffer(str.substring(0, str.indexOf(".")));
25 
26             int j = 0;
27             for (int i = head.length() - 1; i > 0; i--) {
28                 if (head.charAt(i) != ',' && ++j == 3) {
29                     head.insert(i, ",");
30                     j = 0;
31                 }
32             }
33             if (flag == true) {
34                 System.out.print(head + tail + "
");
35             } else {
36                 System.out.print("(" + head + tail + ")"  + "
");
37             }
38         }
39 
40     }
41 
42 }
43