第五次作业 第三章例题

3-1
import java.util.Scanner;
public class Add {
	public static void main(String[] args) {
		int number1=(int)(System.currentTimeMillis()%10);//随机产生第一个整数
		int number2=(int)(System.currentTimeMillis()/7%10);//随机产生第二个整数
		Scanner input=new Scanner(System.in);
		System.out.println("What is" + number1 + "+" + number2 + "?");
		int answer=input.nextInt();//得到答案
		System.out.println(number1 + "+" + number2 + "=" + answer + "is" + (number1+number2==answer));//用布尔表达式给答案打分
	}
	
}

　　

 3-2

import java.util.Scanner;
public class Simple {

	public static void main(String[] args) {
		// TODO Auto-generated method stub
		Scanner input =new Scanner(System.in);
		System.out.println("Enter an integer: ");//输入一个整数
		int number=input.nextInt();
		if (number % 5 == 0)
			System.out.println("HiFive");//如果能被5整除就显示HiFive
		if (number % 2 == 0)
			System.out.println("HiEven");//如果能被2整除就显示HiEven
		
	}

}

　　

3-3

import java.util.Scanner;
public class Sub {

	public static void main(String[] args) {
		// TODO Auto-generated method stub
		int number1 = (int)(Math.random() * 10);
		int number2 = (int)(Math.random() * 10);//随机产生两个一位数的整数
		if(number1<number2) {
			int temp=number1;
			number1=number2;
			number2=temp;//如果number1>number2，交换number1和number2
		}
		System.out.println("Whis is" + number1 + "-" + number2 + "?");
		Scanner input = new Scanner(System.in);
		int answer = input.nextInt();
		if (number1 -number2 == answer)//检查输入的答案，并显示答案是否正确
			System.out.println("You are correct.");
		else {
			System.out.println("Your answer is wrong.");
			System.out.println(number1 + "-" + number2 +" should be " + (number1-number2));
		}
	}

}

　　

3-4 

import java.util.Scanner;
public class Com {

	public static void main(String[] args) {
		// TODO Auto-generated method stub
		Scanner input = new Scanner(System.in);
		System.out.print("Enter weight in kilograms:");//提示用户输入以千克为单位的体重
		double weight = input.nextDouble();
		System.out.print("Enter height in meters:");//提示用户输入以米为单位的身高
		double height = input.nextDouble();
		double bmi = weight / (height * height);//计算BMI
		System.out.println("BMI is " + bmi);
		if (bmi < 18.5)
			System.out.println("Underweight");//体重过轻
		else if (bmi < 25)
			System.out.println("Normal");//标准
		else if (bmi < 30)
			System.out.println("Overweight");//过重
		else
			System.out.println("Obese");//肥胖
	}

}

　　

3-5

import java.util.Scanner;
public class ComputeTax {

    public static void main(String[] args) {
        // TODO Auto-generated method stub
        Scanner input = new Scanner(System.in);
        System.out.print("Enter the taxable income: ");//提示用户输入收入
        double income = input.nextDouble();
        double tax =0;
        if (income <= 8350)//用分支语句计算不同收入应征税
            tax = income * 0.10;
        else if (income <= 33950)
            tax = 8350 * 0.10 + (income - 8350) * 0.15;
        else if (income <= 82250)
            tax = 8350 * 0.10 + (33950 - 8350) * 0.15 + (income - 33950) * 0.25;
        else if (income <= 171550)
            tax = 8350 * 0.10 + (33950 - 8350) * 0.15 + (82250 - 33950) * 0.25 + (income - 82250) * 0.28;
        else if (income <= 372950)
            tax = 8350 * 0.10 + (33950 - 8350) * 0.15 + (82250 - 33950) * 0.25 + (171550 - 82250) * 0.28 + (income - 171550) * 0.33;
        else
            tax = 8350 * 0.10 + (33950 - 8350) * 0.15 + (82250 - 33950) * 0.25 + (171550 - 82250) * 0.28 + (372950 - 171550) * 0.33 + (income - 372950) * 0.35;
        System.out.println("Tax is " + (int)(tax * 100)/100.0);
    }
}

3-6

import java.util.Scanner;
public class Test {

	public static void main(String[] args) {
		// TODO Auto-generated method stub
		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.");//检验一个数是否能同时被2和3整除
		if (number % 2 == 0 || number % 3 ==0)
			System.out.println(number + " is divisible by 2 or 3.");//检验一个数是否能被2或3整除
		if (number % 2 == 0 ^ number % 3 == 0)
			System.out.println(number + " is divisible by 2 or 3,but not both.");//检验一个数是否能被2或3整除，但不能同时被这两个数整除
	}

}

　　

3-7

import java.util.Scanner;
public class Leap {

    public static void main(String[] args) {
        // TODO Auto-generated method stub
        Scanner input = new Scanner(System.in);
        System.out.println("Enter a year: ");
        int year = input.nextInt();
        boolean isLeapYear =(year % 4 == 0 && year % 100 != 0) || (year % 400 == 0);//如果某年可以被4整除而不能被100整除，或者可以被400整除，那么这一年就是闰年200
        System.out.println(year + " is a leap year? " + isLeapYear);
    }

}

3-8

import java.util.Scanner;
public class Lottery {

    public static void main(String[] args) {
        // TODO Auto-generated method stub
        int lottery =(int)(Math.random() * 100);
        Scanner input = new Scanner(System.in);
        System.out.print("Enter your lottery pick (two digits): ");
        int guess = input.nextInt();//用户输入一个猜测的数值
        int lottery1 = lottery / 10;//得到lottery的十位数的数值
        int lottery2 = lottery % 10;//得到lottery的个位数的数值
        int guess1 = guess / 10;
        int guess2 = guess % 10;
        System.out.println("The lottery number is " + lottery);
        if (guess == lottery)
            System.out.println("Exact match: you win $10,000");
        else if (guess2 == lottery1 && guess1 == lottery2)
            System.out.println("Exact match: you win $3,000");
        else if (guess1 == lottery1 || guess1 == lottery2 || guess2 == lottery1 || guess2 == lottery2)
            System.out.println("Exact match: you win $1,000");
        else
            System.out.println("Sorry, no match.");
    }

}

3-9

import java.util.Scanner;
public class Zodia {

    public static void main(String[] args) {
        // TODO Auto-generated method stub
        Scanner input = new Scanner(System.in);
        System.out.print("Enter a year: ");
        int year = input.nextInt();//输入年份
        switch (year %12) {
        case 0:System.out.println("monkey");break;
        case 1:System.out.println("rooster");break;//鸡
        case 2:System.out.println("dog");break;
        case 3:System.out.println("pig");break;
        case 4:System.out.println("rat");break;//鼠
        case 5:System.out.println("ox");break;//牛
        case 6:System.out.println("tiger");break;
        case 7:System.out.println("rabbit");break;//兔
        case 8:System.out.println("dragon");break;
        case 9:System.out.println("snake");break;
        case 10:System.out.println("horse");break;//马
        case 11:System.out.println("sheep");//羊
        }
    }

}