第三周作业

1.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 javazy;
import java.util.Scanner;
public class one {
public static void main(String[] args) {
        // TODO Auto-generated method stub
    System.out.print("输入年份：");
    Scanner sc=new Scanner(System.in);
    String str=sc.nextLine();
    if(str.length()!=4){
        System.out.print("请输入正确的四位数！");
        return;
    }
    int year=Integer.parseInt(str);
        if((year%4==0&&year%100!=0||year%400==0))
            System.out.print(year+"是闰年!"); 
        }else{
          System.out.print(year+"不是闰年!");  
        }
}


}

2.输入一个4位会员卡号,如果百位数字是3的倍数,就输出是幸运会员,否则就输出不是.

package javazy;

import java.util.Scanner;

public class two {

    public static void main(String[] args) {
        // TODO Auto-generated method stub
         Scanner input=new Scanner(System.in);
         System.out.println("请输入四位卡号");
         int a=input.nextInt();
         if((a%1000/100)%3==0){
             System.out.println("是幸运会员");
         }else{
             System.out.println("不是幸运会员");
         }
          
    }
               }

3.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 javazy;

import java.util.Scanner;

public class three {

    public static void main(String[] args) {
        // TODO Auto-generated method stub
                Scanner input= new Scanner(System.in);
                System.out.println("输入x的值");
                float x=input.nextInt();
                float y;
                if(x>0){
                    y=x+3;
                }else if(x==0){
                    y=0;
                }else{
                    y=x*x-1;
                }
                System.out.println(y);
    }

}

4.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 javazy;

import java.util.Scanner;

public class four {

    public static void main(String[] args) {
        // TODO Auto-generated method stub
        Scanner sc= new Scanner(System.in);
        System.out.println("请输入第一个数：");
        double x= sc.nextDouble();
        System.out.println("请输入第二个数：");
        double y= sc.nextDouble();
        System.out.println("请输入第三个数：");
        double z= sc.nextDouble();
        double i=x+y;
        double h=x+z;
        double l=y+z;
        if(x>=l || y>=h || z>=i) {
            System.out.println("不能构成三角形");
        }else {
            System.out.println("能构成三角形");
        }
    }

}