8

//题目3.7
import java.util.Scanner;
public class L {

    @SuppressWarnings("resource")
    public static void main(String[] args) {
             Scanner input = new Scanner(System.in);
            System.out.print("Enter a year:");
            int year = input.nextInt();
            boolean isLeapYear = (year % 4 == 0 && year % 100 != 0) || (year % 400 == 0);
            System.out.println(year + " is a leap year?" +"
"+ isLeapYear);
    }
}

//题目3.6
import java.util.Scanner;
public class L {

    @SuppressWarnings("resource")
    public static void main(String[] args) {
         Scanner input = new Scanner(System.in);

            System.out.print("Enter an integer:");
            int number = input.nextInt();
            if (number % 2 == 0 && number % 3 ==0)
                System.out.println(number + " is divisible by 2 and 3.");
            if (number % 2 == 0 || number % 3 ==0)
                System.out.println(number + " is divisible by 2 or 3.");
            if (number % 2 == 0 ^ number % 3 ==0)
                System.out.println(number + " is divisible by 2 or 3, but not both.");
    }
}

// 题目3.7
import java.util.Scanner;
public class L {

    @SuppressWarnings("resource")
    public static void main(String[] args) {
             Scanner input = new Scanner(System.in);
            System.out.print("Enter a year:");
            int year = input.nextInt();
            boolean isLeapYear = (year % 4 == 0 && year % 100 != 0) || (year % 400 == 0);
            System.out.println(year + " is a leap year?" +"
"+ isLeapYear);
    }
}
//  题目3.6
import java.util.Scanner;
public class L {

    @SuppressWarnings("resource")
    public static void main(String[] args) {
         Scanner input = new Scanner(System.in);

            System.out.print("Enter an integer:");
            int number = input.nextInt();
            if (number % 2 == 0 && number % 3 ==0)
                System.out.println(number + " is divisible by 2 and 3.");
            if (number % 2 == 0 || number % 3 ==0)
                System.out.println(number + " is divisible by 2 or 3.");
            if (number % 2 == 0 ^ number % 3 ==0)
                System.out.println(number + " is divisible by 2 or 3, but not both.");
    }
}


 
//题目3.4
import java.util.Scanner;
public class L {

    @SuppressWarnings("resource")
    public static void main(String[] args) {
        Scanner input = new Scanner(System.in);

        System.out.print("Enter weight in kilograms:");
        double weight = input.nextDouble();

        System.out.print("Enter height in meters:");
        double height = input.nextDouble();

        double bmi = weight/(height * height);

        System.out.println("BMI is " + bmi);
        if (bmi < 18.5)
            System.out.println("Underweight");
        else if (bmi < 25)
            System.out.println("Normal");
        else if (bmi < 30)
            System.out.println("Overweight");
        else
            System.out.println("Obese");
    }
}

 
// 题目3.3
import java.util.Scanner;
public class L {

    @SuppressWarnings("resource")
    public static void main(String[] args) {
        int number1 = (int)(Math.random() * 10);
        int number2 = (int)(Math.random() * 10);

        if (number1 < number2)
        {
            int temp = number1;
            number1 = number2;
            number2 = temp;
        }
        System.out.println("What is " + number1 + "-" + number2 + "?");
        Scanner input = new Scanner(System.in);
        int answer = input.nextInt();
        if (number1 - number2 == answer)
            System.out.println("You are correct!");
        else{
            System.out.println("Your answer is wrong.");
            System.out.println(number1 + "-" + number2 + "should be " + (number1-number2));
        }
    }
}
// 题目3.2
import java.util.Scanner;
public class L {

    @SuppressWarnings("resource")
    public static void main(String[] args) {
        Scanner input = new Scanner(System.in);
        System.out.println("Enter an integer:");
        int number = input.nextInt();
        if (number % 5 == 0)
            System.out.println("HiFive");
        if(number % 2 == 0)
            System.out.println("HiEven");
    }
}


// 题目3.1
import java.util.Scanner;
public class L {

    public static void main(String[] args) {
          int number1=(int)(System.currentTimeMillis()%10);
            int number2=(int)(System.currentTimeMillis()/7%10);
            @SuppressWarnings("resource")
            Scanner input=new Scanner(System.in);
            System.out.println("What is "+number1+"+"+number2+"?");
            int answer = input.nextInt();
            System.out.println(number1+"+"+number2+"="+answer+" is "+(number1+number2==answer)); 
    }
}