第五周上机作业

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）

2.在控制台输出以下图形（知识点：循环语句、条件语句）

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）

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）

1.
package com.itheima01;
import java.util.Scanner;
public class Day01 {

    public static void main(String[] args) { 
         int a,b,c;
          System.out.println("三位数中所有水仙花数：");
          for(int n = 100;n<1000;n++){
              a=n/100;
              b=n%100/10;
              c=n%10;
              if(a*a*a+b*b*b+c*c*c==n){
                  System.out.println(n);
              }
          }
        
        }
    }


2.1  
package com.itheima01;
import java.util.Scanner;
public class Day01 {

    public static void main(String[] args) { 
          for(int i=1;i<=6;i++){
              for(int j=1;j<=i;j++){
                  System.out.print(j);
              }
            System.out.println();  
          }
        }
    }
2.2
package com.itheima01;
import java.util.Scanner;
public class Day01 {

    public static void main(String[] args) { 
          for(int i=6;i>=1;i--){
              for(int j=1;j<=i;j++){
                  System.out.print(j);
              }
            System.out.println();  
          }
        }
    }
2.3
package com.itheima01;
import java.util.Scanner;
public class Day01 {

    public static void main(String[] args) {    
         for (int i = 1; i <= 6; i++)
            {
                for (int j = 6; j > i; j--)
                {
                    System.out.print(" ");
                }
                for (int j = i; j > 0; j--)
                {
                    System.out.print(j);
                }
                System.out.println();
            }
            System.out.println();
        }
    }
2.4
package com.itheima01;
import java.util.Scanner;
public class Day01 {

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


3.package com.itheima01;
import java.util.Scanner;
public class Day01 {

    public static void main(String[] args) { 
        Scanner input=new Scanner(System.in);
        System.out.println("year");
        int year = input.nextInt();
        
        System.out.println("month");
        int month = input.nextInt();
        
        System.out.println("day");
        int day = input.nextInt();
        int total=0;
        for (int i=1;i<month;i++){
            switch(i){
            case 4:
            case 6:
            case 9:
            case 11:
                total+=30;
                break;
            case 2:
                if(year%4==0&&year%100!=0||year%400==0)
                    total+=29;
                else
                        total+=28;
                        break;
            default:
                total+=31;
                break;
                }
            }
            total+=day;
            System.out.println("该天是第"+total+"天");
        }
        
        }


4.package com.itheima01;
import java.util.Scanner;
public class Day01 {

    public static void main(String[] args) { 
         Scanner sc = new Scanner(System.in);
         System.out.println("请输入一个四位数");
         int i = sc.nextInt();
         if(i>=1000&&i<10000){
             int ge = i%10;
             int shi = i%100/10;
             int bai = i%1000/100;
             int qian = i/1000;
             int sum = qian+bai*10+shi*100+ge*1000;
             System.out.println(sum);
         }else{
             System.out.println("NO!");
         }

        }
    }