第一次实验

import java.util.*;

public class GuessNumber

{     

     public static void main (String args[ ])

     { 

           System.out.println("给你一个1至100之间的整数,请猜测这个数");

           int realNumber=(int)(Math.random()*100)+1;

   int yourGuess=0;

           Scanner reader=new Scanner(System.in);     

           System.out.println("输入您的猜测:");

           yourGuess =reader .nextInt(); // reader调用方法获取用户从键盘键入的整数，并赋值给yourGuess

       while (yourGuess!=realNumber)  // 循环条件。

       {

         if (yourGuess>realNumber)  // 条件代码。

          {

              System.out.println("猜大了,请再猜:");

             yourGuess =reader .nextInt(); // reader调用方法获取用户从键盘键入的整数，并赋值给yourGuess

           }

         else if(yourGuess<realNumber)  // 条件代码

           {

               System.out.println("猜小了,请再猜:");

              yourGuess =reader .nextInt(); // reader调用方法获取用户从键盘键入的整数，并赋值给yourGuess

           }

       }

      System.out.println("猜对了!");

   }

  

 

 

 

 

 

 

 

 

 

 

判断一个5位以内的数是几位数，并且判断其是否为回纹数

import java.util.*;

public class Number

{  

    public static void main(String args[ ])

    {

        int number=0,d5,d4,d3,d2,d1;

        Scanner reader=new Scanner(System.in);     

        System.out.println("从键盘输入一个1至99999之间的数");

        while(reader.hasNextInt())  

         {

           number=reader.nextInt();

           if(number>=1&&number<=99999)    // 判断number在1至99999之间的条件

            {

                d5=number%100000/10000;// 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>=1&&d5<=9)  // 判断number是5位数的条件

                {

                  System.out.printf("\n%d是5位数", number);

                  if (d1==d5&&d2==d4)  // 判断number是回文数的条件

                   {

                     System.out.printf("\t%d是回文数", number);

                   }

                  else 

                   { 

                     System.out.printf("\t%d不是回文数", number);

                   }

                }

              else  if(d4>=1&&d4<=9)   // 判断number是4位数的条件

                {

                   System.out.printf("\n%d是4位数",number);

                   if (d1==d4&&d2==d3)  // 判断number是回文数的条件码

                   {

                      System.out.printf("\t%d是回文数", number);

                   }

                  else 

                   { 

                     System.out.printf("\t%d不是回文数",number);

                   }

                }

                else  if(d3>=1&&d3<=9)  // 判断number是3位数的条件

                {

                   System.out.printf("\n%d是3位数", number);

                   if (d1==d3) // 判断number是回文数的条件

                   {

                      System.out.printf("\t%d是回文数", number);

                   }

                  else 

                   { 

                     System.out.printf("\t%d不是回文数", number);

                   }

                }

             else if(d2!=0)

                {

                   System.out.printf("\n%d是2位数", number);

                   if(d1==d2)

                   {

                      System.out.printf("\t%d是回文数", number);

                   }

                  else 

                   { 

                     System.out.printf("\t%d不是回文数", number);

                   }

                }

             else if(d1!=0)

                {

                   System.out.printf("\n%d是1位数", number);

                   System.out.printf("\t%d是回文数", number);

                }

            }

         else

            {

               System.out.printf("\n%d不在1至99999之间", number);

            }

         System.out.printf("%n可继续输入整数, 或输入非整数结束程序%n");

        }

      System.out.println("你输出的数据不是整数");