1. 打印出所有的"水仙花数
package week4;
import java.util.Scanner;
public class Work1 {
public static void main(String[] args) {
// TODO Auto-generated method stub
//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
Scanner input=new Scanner(System.in);
int g,s,b,he;
for(int i=100;i<=999;i++){
g=i%10;
s=i%100/10;
b=i/100;
he=g*g*g+s*s*s+b*b*b;
if(he==i){
System.out.println(i);
}
}
}
}
2.在控制台输出以下图形
（1）
package week4;
public class Work2 {
public static void main(String[] args) {
// TODO Auto-generated method stub
for(int i=1;i<7;i++) {
for(int j=1;j<=i;j++) {
System.out.print(j);
}
System.out.println();
}
}
}
（2）
package week4;
public class Work22 {
public static void main(String[] args) {
// TODO Auto-generated method stub
for(int a=1;a<7;a++) {
for(int b=1;b<=7-a;b++) {
System.out.print(b);
}
System.out.println();
}
}
}
（3）
package week4;
public class Work23 {
public static void main(String[] args) {
// TODO Auto-generated method stub
for(int a=1;a<7;a++) {
for(int b=a;b>0;b--) {
System.out.print(b);
}
System.out.println();
}
}
}
（4）
package week4;
public class Work23 {
public static void main(String[] args) {
// TODO Auto-generated method stub
for(int a=1;a<7;a++) {
for(int b=a;b>0;b--) {
System.out.print(b);
}
System.out.println();
}
}
}
3. 输入年月日，判断这是这一年中的第几天
package week4;
import java.util.Scanner;
public class Work3 {
public static void main(String[] args) {
// TODO Auto-generated method stub
int x = 0;
Scanner sc = new Scanner(System.in);
System.out.print("请输入年份");
int year = sc.nextInt();
System.out.print("请输入月份");
int month = sc.nextInt();
System.out.print("请输入日期");
int day = sc.nextInt();
for (int i = 1; i < month; i++) {
switch (i) {
case 4:
case 6:
case 9:
case 11:
x += 30;
break;
case 2:
if (year % 4 == 0 && year % 100 != 0 || year % 400 == 0)
x += 29;
else
x += 28;
break;
default:
x += 31;
break;
}
}
x += day;
System.out.println("该天是第" + x + "天");
}
}
4．由控制台输入一个4位整数，求将该数反转以后的数
package week4;
import java.util.Scanner;
public class Work4 {
public static void main(String[] args) {
// TODO Auto-generated method stub
Scanner input = new Scanner(System.in);
System.out.println("输入一个四位数");
int a = input.nextInt();
int g, s, b, q;
g = a % 10;
s = a / 10 % 10;
b = a / 100 % 10;
q = a / 1000;
System.out.println("反转后的四位数是" + g + s + b + q);
}
}