第三次作业

1.package finish;
import java.util.*;
public class csy {
    public static void main(String[] args) {
         System.out.println("请输入一个年份：");
            Scanner sc = new Scanner(System.in);
            int a = sc.nextInt();
            if(a%4==0 && a%100 !=0 ||a%400==0){
                System.out.println("是闰年");
            }else{
                System.out.println("不是闰年");
            }
            
        }

    }

2.package finish;
import java.util.*;
public class csy {
    public static void main(String[] args) {
         System.out.println("请输入一个会员卡号：");
            Scanner sc = new Scanner(System.in);
            int a = sc.nextInt();
            if((a /100%10) %3 ==0){
                System.out.println("是幸运会员");
            }else{
                System.out.println("不是幸运会员");
            }
            
        }

    }

3.package finish;
import java.util.*;
public class csy {
    public static void main(String[] args) {
         Scanner SC=new Scanner(System.in);
            System.out.println("请输入x");
            double x=SC.nextDouble();
            double y;
            if(x > 0){
                y = (x + 3);
            }else if(x == 0){
                y = 0;
            }else{
                y = x*2-1;
            }
            System.out.println("输出y的值" +y);
        }

    }

4.package finish;
import java.util.*;
public class csy {
    public static void main(String[] args) {
           Scanner SC=new Scanner(System.in);
            System.out.println("请输入三个数");
            double x=SC.nextDouble();
            double y=SC.nextDouble();
            double z=SC.nextDouble();
            if((x+y)>z && (x+z)>y && (y+z)>x){
                System.out.println("可以构成三角形");
            }else{
                System.out.println("不能构成三角形");
            }
            
        }

    }