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 learn;
import java.util.Scanner;
public class day03 {
public static void main(String[] args) {
// TODO Auto-generated method stub
Scanner input = new Scanner(System.in);
System.out.println("请输入一个年份");
int year = input.nextInt();
if (year % 4 == 0 || year % 400 == 0 && year % 100 != 0 ) {
System.out.println("此年份是闰年");
}else {
System.out.println("此年份不是闰年");
}
}
}

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 learn;
import java.util.Scanner;
public class day03 {
public static void main(String[] args) {
// TODO Auto-generated method stub
Scanner input = new Scanner(System.in);
System.out.println("请输入一个四位数的会员卡号");
int number = input.nextInt();
int bai = number % 1000 / 100 ;
if (bai % 3 == 0) {
System.out.println("您是幸运会员");
}else {
System.out.println("您不是幸运会员");
}
}
}

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 ) x2 –1 ( x < 0 )
package learn;
import java.util.Scanner;
public class day03 {
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X的值");
int X = input.nextInt();
if (X>0) {
System.out.println("y=" + (X+3));
}else if (X==0) {
System.out.println("y=" + 0);
}else if (X<0) {
System.out.println("y=" + (2*X-1));
}else {
System.out.println("无结果");
}
}
}

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 learn;
import java.util.Scanner;
public class day03 {
public static void main(String[] args) {
// TODO Auto-generated method stub
Scanner input = new Scanner(System.in);
System.out.println("请输入第一个数");
int a = input.nextInt();
System.out.println("请输入第二个数");
int b = input.nextInt();
System.out.println("请输入第三个数");
int c = input.nextInt();
if (a+b>c && b+c>a && a+c>b) {
System.out.println("这三位数可构成三角形");
}else {
System.out.println("这三个数不可构成三角形");
}
}
}

来源:https://www.cnblogs.com/xiaomoa/p/12557845.html