第五周上机练习

1. 打印出所有的"水仙花数"，所谓"水仙花数"是指一个三位数，其各位数字立方和等于该数本身。例如：153是一个"水仙花数"，因为153=1的三次方＋5的三次方＋3的三次方。（知识点：循环语句、条件语句）

package diyici;
import java.util.*;

import org.omg.Messaging.SyncScopeHelper;

public abstract class diyici{ 
    public ArrayList<Integer> getSXHS() {
        // TODO Auto-generated method stub
        ArrayList<Integer> sxhs = new ArrayList<Integer>();
        for(int i = 100; i <= 999; i++){
            int i1 = i / 100;
            int temp = i % 100;
            int i2 = temp / 10;
            int i3 = temp % 10;
            int iresult = (int) (Math.pow(i1, 3) + Math.pow(i2, 3) + Math.pow(i3, 3));
            if(i == iresult) {
                sxhs.add(new Integer(i));
            }
        }
        return sxhs;
    }
    }

2.在控制台输出以下图形（知识点：循环语句、条件语句）

package diyici;
import java.util.*;

import org.omg.Messaging.SyncScopeHelper;

public abstract class diyici{ 
     
    
    public static void main(String[] args)
    {
    
      for(int i=0; i<=7; i++){
         for(int j=1; j<i; j++){
             
             System.out.print(j);
          
             }
            System.out.println("");
      } 
}}

package diyici;
import java.util.*;

import org.omg.Messaging.SyncScopeHelper;

public abstract class diyici{ 
     
    
    public static void main(String[] args)
    {
    
        int i=1;
          int j=1;
          for(i=6;i>0;i--){
              for(j=1;j<=i;j++){
                  System.out.print(j);
              }
              System.out.println();
          }         
    }

}

package diyici;
import java.util.*;

import org.omg.Messaging.SyncScopeHelper;

public abstract class diyici{ 
     
    
    public static void main(String[] args)
    {
    
        for(int i=1;i<7;i++) {
            for (int k = 1; k <7-i ; k++) {
                System.out.print(" ");
            }
            for(int j=i;j>0;j--) {
                System.out.print(j);
            }
            System.out.println();
        }
    }}

package diyici;
import java.util.*;

import org.omg.Messaging.SyncScopeHelper;

public abstract class diyici{ 
     
    
    public static void main(String[] args)
    {
         for(int i=6;i>0;i--) {
                for(int k=0;k<6-i;k++) {
                    System.out.print(" ");
                }
                for(int j=1;j<=i;j++) {
                    System.out.print(j);
                }
                System.out.println("");

    }
    }}

3. 输入年月日，判断这是这一年中的第几天（知识点：循环语句、条件语句）

package diyici;
import java.util.*;

import org.omg.Messaging.SyncScopeHelper;

public abstract class diyici{ 
     
        public static void main(String[] args) {
            // TODO Auto-generated method stub
         System.out.print("请输入年，月，日\n");
         Scanner input = new Scanner(System.in);
         int year = input.nextInt();
         int month = input.nextInt();
         int date= input.nextInt();
         int sum =0 ;
         int leap;
        //计算某一月份之前的天数
         switch(month) {
           case 1 :
               sum=0;break;
           case 2 :
               sum =31;break;
           case 3:
               sum=59;break;
           case 4:
               sum =90;break;
           case 5:
               sum = 120;break;
           case 6:
               sum = 151;;break;
           case 7:
               sum = 181;break;
           case 8:
               sum = 212;break;
           case 9:
               sum = 243;break;
           case 10:
               sum = 273;break;
           case 11:
               sum = 303;break;
           case 12:
                sum = 334;break;
           default:
               System.err.println("date error");break;
         }
         sum = sum + date;
         if(year%400==0||year%4==0&&year%100!=0) {
             leap = 1;
         }else {
             leap =0;
         }
          if(leap==1&&month>2) {
              sum++;
          }
          System.out.println(sum);
        //加上当月的date         
        }
    }

4．由控制台输入一个4位整数，求将该数反转以后的数，如原数为1234，反转后的数位4321（知识点：循环语句、条件语句）

package diyici;
import java.util.*;

import org.omg.Messaging.SyncScopeHelper;

public abstract class diyici{ 
     
     
        public static void main(String[] args) {
            Scanner sc = new Scanner(System.in);
            int shuru = sc.nextInt();
            String hebing ="";
            
            String fanzhuan = String.valueOf(shuru);
            for(int i=fanzhuan.length()-1; i>=0; i--) {
                //System.out.print(fanzhuan.charAt(i));
                hebing = hebing + fanzhuan.charAt(i);//将数字拆开，重新组合形成一个字符串
            }
            int newShu = Integer.parseInt(hebing);//将新数转回int类型
            System.out.print(newShu);
        }
    }