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 xx;
public class pika {
public static void main(String[] args) {
int g,s,b,sum=0;
for(int i = 100;i<=999;i++) {
g=i%10;
s=i/10%10;
b=i/100;
sum=g*g*g+s*s*s+b*b*b;
if(sum==i) {
System.out.print(i+" ");
}
}
}
}
2.在控制台输出以下图形（知识点：循环语句、条件语句）
package xx;
import java.util.Scanner;
public class pika {
public static void main(String[] args) {
for(int i = 1; i <= 6; i++) {
for(int j = 1; j <= i; j++) {
System.out.print(j+" ");
}
System.out.println();
}
}
}
package xx;
import java.util.Scanner;
public class pika {
public static void main(String[] args) {
for(int i = 1; i <= 6; i++) {
for(int j = 1; j <= 7-i; j++) {
System.out.print(j+" ");
}
System.out.println();
}
}
}
package xx;
import java.util.Scanner;
public class pika {
public static void main(String[] args) {
for(int i = 1; i <= 6; i++) {
for(int j = i; j >= 1; j--) {
System.out.print(j+" ");
}
System.out.println();
}
}
}
package xx;
public class pika {
public static void main(String[] args) {
for (int a = 6; a >= 1; a--) {
for (int i = 1; i <= 7 - a; i++) {
System.out.print(" ");
}
for (int j = 1; j <= a; 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 li;
import java.util.Scanner;
public class Test05{
public static void main(String[] args) {
int year;
int mouth;
int day = 0;
int days;
int d = 0; // 累计天数
int e = 0;
Scanner scanner = new Scanner(System.in);
//判断输入的年份和月份和日期是否错误
do {
System.out.println("输入年:");
year = scanner.nextInt();
System.out.println("输入月:");
mouth = scanner.nextInt();
System.out.println("输入日:");
days = scanner.nextInt();
if (year < 0 || mouth < 0 || mouth > 12 || days < 0 || days > 31) {
System.out.println("input error!");
e = 1;
}
} while (e == 1);
for (int i = 1; i < mouth; i++) {
switch (i) {
case 1:
case 3:
case 5:
case 7:
case 8:
case 10:
case 12: {
day = 31;
break;
}
case 4:
case 6:
case 9:
case 11: {
day = 30;
break;
}
case 2: {
if ((year % 100 != 0 && year % 4 == 0) || (year % 100 == 0 && year % 400 == 0)) {
day = 29;
} else {
day = 28;
}
}
default:
break;
}
d += day;
}
System.out.println("这是" + year + "年的" + (d + days) + "天");
}
}
package li;
import java.util.Scanner;
public class Test05 {
public static void main(String[] args) {
int a, b, c, d, e, x;
Scanner sc = new Scanner(System.in);
System.out.println("输入数字：");
e = sc.nextInt();
a = e / 1000;
b = e / 100 % 10;
c = e / 10 % 10;
d = e % 10;
x = d * 1000 + c * 100 + b * 10 + a;
System.out.println("反转后数为：" + x);
}
}
