1. X (x<1)Y= 2x-1 (1<x<10)3x-11 (x>10) 要求输入x值后，输出y值。

package student.xiaoqiao.day01;import java.util.Scanner；public class Yi {public static void main(String[] args) {System.out.println("请输入一个数");Scanner sc = new Scanner(System.in);int x = sc.nextInt();if (x < 1) {System.out.println("y=" + x);}if (x > 1 & x < 10) {System.out.println("y=" + (2 * x - 1));}if (x > 10) {System.out.println("y=" + (3 * x - 11));}}}2.输入一个年份判断year是否是闰年package student.xiaoqiao.day01;import java.util.Scanner;public class Er {public static void main(String[] args) {System.out.println("请输入年份");Scanner sc=new Scanner(System.in);int year=sc.nextInt();if((year%4==0&year%100!=0)|(year%400==0)) System.out.println("是闰年");elseSystem.out.println("不是闰年");}}3.任意输入a,b,c 3个数判断a，b，c大小package student.xiaoqiao.day01;import java.util.Scanner;public class San {public static void main(String[] args) {System.out.println("请输入三个数（加空格或回车）:");Scanner sc = new Scanner(System.in);int x = sc.nextInt();int y = sc.nextInt();int z = sc.nextInt();if (x > y & x > z) {System.out.println(x);} else if (x < y & z < y) {System.out.println(y);} else if (x < z & y < z) {System.out.println(z);}}}4_1输出图形*********package student.xiaoqiao.day01;public class Si_1 {public static void main(String[] args) {int temp = 3;for (int i = 1; i <= temp; i++) {for (int j = 1; j <= temp - i; j++) {System.out.print(" ");}for (int k = 1; k <= 2 * i - 1; k++) {System.out.print("*");}System.out.print('\n');}}}4_2输出图形*********package student.xiaoqiao.day01;public class Si_1 {public static void main(String[] args) {int temp = 3;for (int i = 1; i <= temp; i++) {for (int j = 1; j <= temp - i; j++) {System.out.print(" ");}for (int k = 1; k <= 2 * i - 1; k++) {System.out.print("*");}System.out.print('\n');}}4_3输出图形任意输入n当输入n值为1时，输出 *当输入n值为2时，输出当输入n值为3时，输出.。

当输入n值为5时，输出*****************************************package student.xiaoqiao.day01;import java.util.Scanner;public class Si_3 {public static void main(String[] args) {System.out.println("请输入一个数：");Scanner sc=new Scanner(System.in);int temp = sc.nextInt();for (int i = 1; i <= temp; i++) {for (int j = 1; j <= temp - i; j++) {System.out.print(" ");}for (int k = 1; k <= 2 * i - 1; k++) {System.out.print("*");}System.out.print('\n');}for (int i = temp; i >= 1; i--) {for (int j = i-1; j < temp; j++) {System.out.print(" ");}for (int k = 1; k <= 2 * i - 3; k++) {System.out.print("*");}System.out.print('\n');}}}4_4 输出图形***************package student.xiaoqiao.day01;public class Si_4 {public static void main(String[] args) {int temp = 3;for (int i = 1; i <= temp; i++) {for (int j = 1; j <= temp - i; j++) {System.out.print(" ");}for (int k = 1; k <= 2 * i + 1; k++) {System.out.print("*");}System.out.print('\n');}}}4_5 输出图形package student.xiaoqiao.day01;public class Si_5 {public static void main(String[] args) { int temp = 4;for (int i = 1; i <= temp; i++) {for (int k = 1; k <= 5; k++) {System.out.print("*");}System.out.print('\n');}}}5.判断水仙花数输入一个3位数，判断个位，十位与百位的3次方的和是否等于其本身，相等就是水仙花数package student.xiaoqiao.day01;import java.util.Scanner;public class Wu {public static void main(String[] args) {System.out.println("请输入一个三位数");Scanner sc = new Scanner(System.in);int a = sc.nextInt();int b = a / 100;int c = (a / 10) % 10;int d = a % 10;if (a == b * b * b + c * c * c + d * d * d) {System.out.println("此数是水仙花");} else {System.out.println("此数不是水仙花");}}}6. 输入一个x和y，在输入一个字符x, 当输入的字符为‘+’，输出x与y的和，当输入的字符为‘-’，输出x与y的差，当输入的字符为‘*’，输出x与y的积，当输入的字符为‘/’，输出x与y的商.package student.xiaoqiao.day01;import java.util.Scanner;public class Liu {public static void main(String[] args) {System.out.println("请输入一个加减乘除字符");Scanner sc=new Scanner(System.in);char c=sc.next().charAt(0);int x=4;int y=2;switch (c) {case '+':System.out.println("x+y="+(x+y));break;case '-':System.out.println("x-y="+(x-y));break;case '*':System.out.println("x*y="+(x*y));break;case '/':System.out.println("x/y="+(x/y));break;default:System.out.println("输入的字符不合法！");break;}}}7.求数列 0,1,2,32 ,…………….,n n-1 的和要求判断n是否在0到10之间，如果不在提示重新输入，for循环 while循环，do while 都要写一遍。