第五周练习

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）

public class practice_week5 {

    public static void main(String[] args) {
        // TODO Auto-generated method stub
        int ge,shi,bai;
        for (int i = 100; i < 1000; i++) {
            ge = i%10;
            shi= i/10%10;
            bai= i/100;
            if ((ge*ge*ge) + (shi*shi*shi) + (bai*bai*bai)==i) {
                System.out.println("所有水仙花数字：" + i );
            }
        }
    }

}

2.在控制台输出以下图形（知识点：循环语句、条件语句）

public class practice_week5 {

    public static void main(String[] args) {
        // TODO Auto-generated method stub
        for (int i = 1; i <= 6; i++) {
            for (int j = 1; j <= i; j++) {
                System.out.print(j);
            }
            System.out.println();
        }
    }

}

public class practice_week5 {

    public static void main(String[] args) {
        // TODO Auto-generated method stub
        for (int i = 1; i <= 6; i++) {
            for (int j = 1; j <= 7-i; j++) {
                System.out.print(j);
            }
            System.out.println();
        }
    }

}

public class practice_week5 {

    public static void main(String[] args) {
        // TODO Auto-generated method stub
        for (int i = 1; i <= 6; i++) {
            for (int k = 1; k <= 6-i; k++) {
                System.out.print(" ");
            }
            for (int j = i; j >= 1; j--) {
                System.out.print(j);
            }
            System.out.println();
        }
    }

}

public class practice_week5 {

    public static void main(String[] args) {
        // TODO Auto-generated method stub
        for (int i = 1; i <= 6; i++) {
            for (int k = 1; k <= i-1; k++) {
                System.out.print(" ");
            }
            for (int j = 1; j <= 7-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）

import java.time.Month;
import java.util.Scanner;

public class practice_week5 {

    public static void main(String[] args) {
        // TODO Auto-generated method stub
        Scanner input =new Scanner(System.in);
        System.out.println("请输入年份：");
        int year = input.nextInt();
        System.out.println("请输入月份：");
        int month = input.nextInt();
        System.out.println("请输入日期：");
        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("输入的日子为此年的第" + total + "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）

import java.util.Scanner;

public class practice_week5 {

    public static void main(String[] args) {
        // TODO Auto-generated method stub
        Scanner input = new Scanner(System.in);
        System.out.println("请输入一个4位整数：");
        int rumber = input.nextInt();
        int ge = rumber%10;
        int shi = rumber%100/10;
        int bai = rumber%1000/100;
        int qian = rumber/1000;
        int a = ge*1000 + shi*100 + bai*10 + qian ;
        System.out.println("两极反转：" + a);
    }

}