java第五周随堂

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 doom4;

public class thefiveweekclasswork1 {

	public static void main(String[] args) {
		// TODO Auto-generated method stub
		int i = 100;
		for (i = 100; i < 1000; i++) {
			int ge = i % 10;
			int shi = i / 10 % 10;
			int bai = i / 100;
			if (i == bai * bai * bai + shi * shi * shi + ge * ge * ge)
				System.out.println(i + "是一个水仙花数");
		}

	}
}

　　

2

package doom4;

public class thefiveweekclasswork2_1 {

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

	}

}

　　

package doom4;

public class thefiveweekclasswork2_2 {

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

	}

}

　　

package doom4;

public class thefiveweekclasswork2_3 {
	public static void main(String[] args) {
		// TODO Auto-generated method stub
		int i;
		int j;
		for (i = 1; i <= 6; i++) {
			for (j = 1; j <= 7 - i; j++) {
				System.out.print(" ");
			}
			for (j = i; j >= 1; j--)
				System.out.print(j);
			System.out.println();
		}
		System.out.println();

	}

}

　　

package doom4;

public class thefiveweekclasswork2_4 {
	public static void main(String[] args) {
		// TODO Auto-generated method stub
		int i;
		int j;
		for (i = 1; i <= 6; i++) {
			for (j = 1; j <= i; j++) {
				System.out.print(" ");
			}

			for (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）

package doom4;

import java.util.Scanner;

public class thefiveweekclasswork3 {

	public static void main(String[] args) {
		// TODO Auto-generated method stub

		Scanner input = new Scanner(System.in);

		System.out.print("请输入一个年份:");
		int year = input.nextInt();

		System.out.print("请输入一个月份:");
		int month = input.nextInt();

		System.out.print("请输入一个日:");
		int day = input.nextInt();

		int sum = 0;
		for (int i = 1; i < month; i++) {
			switch (i) {
			case 2:
				if (year % 4 == 0 && year % 100 != 0 || year % 400 == 0)
					sum += 29;
				else
					sum += 28;
				break;
			case 1:
			case 3:
			case 5:
			case 7:
			case 8:
			case 10:
			case 12:
				sum += 31;
				break;
			case 4:
			case 6:
			case 9:
			case 11:
				sum += 30;
				break;
			}
		}
		sum += day;
		System.out.println(year + "年" + month + "月" + day + "日" + "是" + year + "年的第" + 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 doom4;

import java.util.Scanner;

public class thefiveweekclasswork4 {

	public static void main(String[] args) {
		// TODO Auto-generated method stub
		Scanner input = new Scanner(System.in);

		System.out.print("请输入一个四位数:");
		int x = input.nextInt();
		int ge = x % 10;
		int shi = x / 10 % 10;
		int bai = x / 100 % 10;
		int qian = x / 1000;
		System.out.print(ge);
		System.out.print(shi);
		System.out.print(bai);
		System.out.print(qian);

	}

}