/*该程序主要判断一个数是不是回文数
 * 结果首先输出这个数十几位数
 * 再输出是不是回文数
 */

import javax.swing.JOptionPane;

public class Number 
{ 
    public static void main(String args[]) 
    { 
         int number=0,d5,d4,d3,d2,d1;

         String str=JOptionPane.showInputDialog("输入一个1至99999之间的数");

         number=Integer.parseInt(str);

         if(number>=1&&number<=99999) //判断number在1至99999之间的条件 
         { 
               d5=number/10000; //计算number的最高位（万位）d5

               d4=number%10000/1000; //计算number的千位d4

               d3=number%1000/100; //计算number的百位d3

               d2=number%100/10;

               d1=number%10;

              if(d5!=0) //判断number是5位数的条件 
              {
               System.out.println(number+"是5位数");
               
               if(d5==d1&&d4==d2) //判断number是回文数的条件 
                  { 
                      System.out.println(number+"是回文数"); 
                  } 
                  
               else 
                 { 
                      System.out.println(number+"不是回文数"); 
                 } 
              } 
               else if(d4!=0) //判断number是4位数的条件 
              { 
                 System.out.println(number+"是4位数"); 
                 
                 if(d4==d1&&d3==d2) //判断number是回文数的条件码 
                 { 
                   System.out.println(number+"是回文数"); 
                 } 
                 else 
                 { 
                   System.out.println(number+"不是回文数"); 
                 } 
              } 
             else if(d3!=0) //判断number是3位数的条件 
            { 
                 System.out.println(number+"是3位数"); 
                 
                 if(d3==d1) //判断number是回文数的条件 
                 { 
                   System.out.println(number+"是回文数"); 
                 } 
                 else 
                { 
                   System.out.println(number+"不是回文数"); 
                 } 
             } 
             else if(d2!=0) 
            { 
                System.out.println(number+"是2位数"); 
                
                if(d1==d2) 
                { 
                   System.out.println(number+"是回文数"); 
                } 
                else 
                { 
                 System.out.println(number+"不是回文数"); 
                } 
            } 
            else if(d1!=0) 
            { 
              System.out.println(number+"是1位数"); 
                 System.out.println(number+"是回文数"); 
            } 
         }
      else 
      { 
       System.out.printf("\n%d不在1至99999之间",number); 
      } 

本文转自 lingdududu 51CTO博客，原文链接：