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.itheima08; public class HelloBudget { public static void main(String[] args ){ int i=100; for(;i<1000;i++){ int ge=i%10; int shi=i/10%10; int bai=i/100%10; if(i==(ge*ge*ge+shi*shi*shi+bai*bai*bai)){ System.out.println(i); } } } } 2.1 package com.itheima08; import java.util.*; public class HelloBudget { public static void main(String[] args ){ for(int i = 1; i <= 6; i++) { for(int j = 0; j < i; j++) { System.out.print(""); } for(int j = 1; j <= i; j++) { System.out.print(j); } System.out.println(); } } } 2.2package com.itheima08; import java.util.*; public class HelloBudget { 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.itheima08; import java.util.*; public class HelloBudget { public static void main(String[] args ){ for(int i = 1;i <= 6;i++) { for(int j = 1;j <= 2 * (6 - i);j++) System.out.print(" "); for(int j = i;j >= 1;j--) System.out.printf(" %d",j); System.out.println(); } System.out.println(); } } 2.4 package com.itheima08; import java.util.*; public class HelloBudget { 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.package com.itheima08; import java.util.*; public class HelloBudget { 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.itheima08; import java.util.*; public class HelloBudget { public static void main(String[] args ){ Scanner input=new Scanner(System.in); System.out.println("请输入一个四位数字"); int i=input.nextInt(); int ge = i / 1000; int shi = i/ 100 % 10; int bai = i / 10 % 10; int qian = i % 10; int j = qian * 1000 + bai * 100 + shi * 10 + ge; System.out.println("反转后 数字为�" + j); } }