JAVA作业。

1.

package text;

import java.util.Scanner;
public class zuoye {

    public static void main(String[] args) {
        //1.输入一个年份,判断是不是闰年(可以被4整除但不能被100整除,或者能被400整除)
        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(a+"年是闰年");
        }else {
            System.out.println(a+"年不是闰年");
        }
    }
}

 

 2.

package text;

import java.util.Scanner;
public class zuoye {

    public static void main(String[] args) {
        //2.输入一个4位会员卡号 如果百位数字是3的倍数 输出幸运会员,否则就不是.
        System.out.print("请输入会员卡号:");
        Scanner sc = new Scanner(System.in);
        int a = sc.nextInt();
        if (a >= 1000 && a <=9999) {
            if(a / 100 % 10 % 3 == 0) {
                System.out.println(a+"是幸运会员");
            }else {System.out.println(a+"不是幸运会员");}
        }else {System.out.println("您的输入有误");}
    }
}

3.

package text;

import java.util.Scanner;
public class zuoye {
        public static void main(String[] args) {
            //已知函数 x 输出y x>0 (x+3) x=0 y=0 x<0 x*2-1
            Scanner sc = new Scanner(System.in);
            System.out.print("请输入x的值:");
            int x = sc.nextInt();
            int y;
            if(x > 0) {
                y = x + 3;
                System.out.println("y值为:"+y);
            }if(x < 0) {
                y = x*2 - 1;
                System.out.println("y值为:"+y);
            }if(x == 0){
                y = 0;
                System.out.println("y值为:"+y);
            }
            }
        }

4.

package text;

import java.util.Scanner;
public class zuoye {
    public static void main(String[] args) {
        //输入三个数 构成三角形;
        Scanner sc = new Scanner(System.in);
        System.out.print("请输入第一个数:");
        int a = sc.nextInt();
        System.out.print(" 请输入第二个数:");
        int b = sc.nextInt();
        System.out.print(" 请输入第三个数:");
        int c = sc.nextInt();
        if((a + b) >= c && (a + c) >= b && (b + c) >= a){
            System.out.println("可构成三角形");
        }else {
            System.out.println("不可以构成三角形");}
        }
        
        
    }