package lll; import java.util.Scanner; public class lll2000 { public static void main(String[] args) { // TODO Auto-generated method stub Scanner input=new Scanner(System.in); System.out.println("输入年份"); int year=input.nextInt(); System.out.println("输入月份"); int m=input.nextInt(); switch(m) { case 4: case 6: case 9: case 11: System.out.println("30天"); break; case 2: if (year%4==0&&year%100==0||year%400==0) { System.out.println("29天"); } else { System.out.println("28天"); } break; default: System.out.println("31天"); break; } } }

2. 给定一个成绩a,使用switch结构求出a的等级
。A:90-100,B:80-89,C:70-79,D:60-69,E:0~59
package lll; import java.util.Scanner; public class lll { public static void main(String[] args) { // TODO Auto-generated method stub Scanner input=new Scanner(System.in); System.out.println("输入成绩"); int a=input.nextInt(); switch(a/10) { case 10: case 9: System.out.println("A"); break; case 8: System.out.println("B"); break; case 7: System.out.println("C"); break; case 6: System.out.println("D"); break; case 5: case 4: case 3: case 2: case 1: case 0: System.out.println("E"); break; } } }

3、输入一个数字,判断是一个奇数还是偶数
package lll; import java.util.Scanner; public class lll { public static void main(String[] args) { // TODO Auto-generated method stub Scanner input=new Scanner(System.in); System.out.println("请输入一个数:"); int a=input.nextInt(); if (a%2==0) { System.out.println("您输入的"+a+"是一个偶数"); } else { System.out.println("您输入的"+a+"是一个奇数"); } } }

4、编写程序, 判断一个变量x的值,如果是1, 输出x=1,如果是5,输出x=5,如果是 10,输出 x=10,除了以上几个值,都输出x=none。
package lll; import java.util.Scanner; public class lll { public static void main(String[] args) { // TODO Auto-generated method stub Scanner input=new Scanner(System.in); System.out.println("输入变量x"); int x=input.nextInt(); if(x==1||x==5||x==10) { switch(x) { case 1: System.out.println("x=1"); break; case 5: System.out.println("x=5"); break; case 10: System.out.println("x=10"); break; } } else { System.out.println("x=none"); } } }

5. 判断一个数字是否能被5和6同时整除(打印能被5和6整除),或只能被5整除(打印能被5整除 ),或只能被6整除,(打印能被6整除),不能被5或6整除,(打印不能被5或6整除)
package lll; import java.util.Scanner; public class lll { public static void main(String[] args) { // TODO Auto-generated method stub Scanner input=new Scanner(System.in); System.out.println("输入一个数"); int a=input.nextInt(); if(a%5==0&&a%6==0) { System.out.println("能被5和6同时整除"); } if(a%5==0&&a%6!=0) { System.out.println("只能被5整除"); } if(a%5!=0&&a%6==0) { System.out.println("只能被6整除"); if(a%5!=0&&a%6!=0) { System.out.println("不能被5或6整除"); } } } }

6. 输入一个年份,判断是不是闰年(能被4整除但不能被100整除,或者能被400整除)
package lll; import java.util.Scanner; public class lll { public static void main(String[] args) { // TODO Auto-generated method stub Scanner input = new Scanner(System.in); System.out.println("输入一个年份"); int year=input.nextInt(); if(year%4==0&&year%100!=0||year%400==0) System.out.println("闰年"); else System.out.println("平年"); } }

7.输入一个4位会员卡号,如果百位数字是随机数,就输出是幸运会员,否则就输出不是.
package lll; import java.util.Random; import java.util.Scanner; public class lll { public static void main(String[] args) { // TODO Auto-generated method stub Scanner input = new Scanner(System.in); Random r=new Random(); System.out.println("输入一个4位会员卡号"); int hao=input.nextInt(); int b=hao/100%10; int a=r.nextInt(10); System.out.println("幸运数是"+a); if (b==a) System.out.println("是幸运会员"); else System.out.println("不是幸运会员"); } }

8.已知函数,输入x的值,输出对应的y的值.
x + 3 ( x > 0 )
y = 0 ( x = 0 )
x*2 –1 ( x < 0 )
package lll; import java.util.Random; import java.util.Scanner; public class lll { public static void main(String[] args) { // TODO Auto-generated method stub Random r=new Random(); Scanner input = new Scanner(System.in); System.out.println("输入x的值"); double x=input.nextDouble(); if(x>0) System.out.println("y的值是"+(x+3)); else if(x==0) System.out.println("y的值是"+0); else System.out.println("y的值是"+(x*2-1)); } }

9.输入三个数,判断能否构成三角形(任意两边之和大于第三边)
package lll; import java.util.Scanner; public class lll { public static void main(String[] args) { // TODO Auto-generated method stub Scanner input=new Scanner(System.in); System.out.println("边长a"); int a=input.nextInt(); System.out.println("边长b"); int b=input.nextInt(); System.out.println("边长c"); int c=input.nextInt(); if (a+b>c&&a+c>b&&b+c>a) { System.out.println("abc可以构成三角形"); } else { System.out.println("abc无法构成三角形"); } } }
