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）

package asdf;

public class cg {

    public static void main(String[] args) {
        // TODO Auto-generated method stub
         for (int i = 100; i < 1000; i++)
            {
                int bai = i / 100;
                int shi = i / 10 % 10;
                int ge = i % 10;
                if (Math.pow(bai, 3) + Math.pow(shi, 3) + Math.pow(ge, 3) == i)
                {
                    System.out.println(i);
                }
            }

    }

}

2.在控制台输出以下图形（知识点：循环语句、条件语句）

package asdf;

public class cg {

    public static void main(String[] args) {
        // TODO Auto-generated method stub
          for (int i = 0; i < 6; i++)
            {
                for (int j = 1; j <= i + 1; j++)
                {
                    System.out.print(j);
                }
                System.out.println();
            }
            System.out.println();
            for (int i = 6; i >= 1; i--)
            {
                for (int j = 1; j <= i; j++)
                {
                    System.out.print(j);
                }
                System.out.println();
            }
            System.out.println();
            for (int i = 0; i < 6; i++)
            {
                for (int j = 5; j > i; j--)
                {
                    System.out.print(" ");
                }
                for (int j = 1; j <= i + 1; j++)
                {
                    System.out.print(j);
                }
                System.out.println();
            }
            System.out.println();
            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.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 asdf;
import java.util.Scanner;
public class cg {

    public static void main(String[] args) {
        // TODO Auto-generated method stub
        int day=0;
        int month=0;
        int year=0;
        int sum=0;
        int leap;
        System.out.print("请输入年，月，日\n");
        Scanner input = new Scanner(System.in);
        year=input.nextInt();
        month=input.nextInt();
        day=input.nextInt();
        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=304;break;
        case 12:
            sum=334;break;
        default:
            System.out.println("data error");break;
            }
        sum=sum+day;
        if(year%400==0||(year%4==0&&year%100!=0))
            leap=1;
        else
            leap=0;
        if(leap==1 && month>2)
            sum++;
        System.out.println("该天是第"+sum+"天");
    }
}

     

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 asdf;
import java.util.Scanner;
public class cg {

    public static void main(String[] args) {
        // TODO Auto-generated method stub
        Scanner s = new Scanner(System.in);
        System.out.println("请输入一个四位数:");
            int num = s.nextInt();
            int ge = num % 10;
            int shi = num / 10 % 10;
            int bai = num / 100 % 10;
            int qian = num / 1000;
         System.out.println("反转后结果为:" + ge + shi + bai + qian);
    }

}