思路就是先计算出int 的长度，然后每次计算出一位数字
/** * Created by lxd on 16-8-6. */ public class Main { public static void main(String[] args) { Scanner cin = new Scanner(System.in); while (cin.hasNext()) { Convert(cin.nextInt()); } cin.close(); } public static void Convert(int num) { boolean isNagive = false; if (num < 0) { isNagive = true; num = 0 - num; } int[] res = new int[14]; int length = 0; int temp = num; if (num == 0) length = 1; while (num != 0) { num = num / 10; res[length] = temp - num * 10; temp = num; length++; } StringBuilder stringBuilder = new StringBuilder(length); for (int i = length - 1; i >= 0; i--) { stringBuilder.append(res[i]); } if (isNagive) System.out.println("-" + stringBuilder.toString()); else System.out.println(stringBuilder.toString()); } }