1. 问题描述

反转一个只有3位数的整数。

2. 示例

输入num=123,输出321，输入num=100，输出1.

3. 代码示例

3.1 python

 1 class Solution:
 2     def reverseInt(self,num):
 3         if isinstance(num,int) and num < 999 and num > 99:
 4             hundreds = int(num/100)  # 百位
 5             tens= int(num%100/10)  # 十位
 6             individual = int(num%10)
 7             return individual * 100 + tens * 10 + hundreds
 8         else:
 9             return ""
10 if __name__ == '__main__':
11     solution = Solution()
12     while True:
13         num = int(input("请输入一个3位整数: "))
14         print(solution.reverseInt(num))

运行效果：

3.2 Java

 1 import java.util.Scanner;
 2 
 3 public class Days001 {
 4 
 5     public int reverseInt(int num) {
 6         if (num > 99 && num < 1000) {
 7             int hundreds = num / 100;  // 百位
 8             int tens = num % 100 / 10;  // 十位
 9             int individual = num % 10; // 个位
10             return individual * 100 + tens * 10 + hundreds;
11         } else {
12             System.out.println("输入的数据超范围");
13             return 0;
14         }
15 
16     }
17 
18     public static void main(String[] args) {
19         Days001 solutionReverse3Int001 = new Days001();
20         while (true) {
21             System.out.print("输入一个3位整数:");
22             Scanner scanner = new Scanner(System.in);
23             int num = scanner.nextInt();
24             int reverseNum = solutionReverse3Int001.reverseInt(num);
25             System.out.println(reverseNum);
26         }
27     }
28 }