使用switch case语句来显示月份的对应天数

方法一：控制台输入月份

package com.liaojianya.chapter1;

import java.util.Scanner;

/**
 * This program demonstrates thw way of implements 
 * display the number of days according to 12 months.
 * @author LIAO JIANYA
 * 2016年7月19日
 */
public class MonthAndDays
{
	public static void main(String[] args)
	{
		System.out.println("please enter a number : 1~12");
		@SuppressWarnings("resource")
		Scanner scan = new Scanner(System.in);
		int month = scan.nextInt();
		switch (month)
		{
		case 1:
			System.out.println("January has 31 days");
			break;
		case 2:
			System.out.println("February has 28 days");
			break;
		case 3:
			System.out.println("March has 31 days");
			break;
		case 4:
			System.out.println("April has 30 days");
			break;
		case 5:
			System.out.println("May has 31 days");
			break;
		case 6:
			System.out.println("June has 30 days");
			break;
		case 7:
			System.out.println("July has 31 days");
			break;
		case 8:
			System.out.println("August has 31 days");
			break;
		case 9:
			System.out.println("September has 30 days");
			break;
		case 10:
			System.out.println("Octor has 31 days");
			break;
		case 11:
			System.out.println("November has 30 days");
			break;
		case 12:
			System.out.println("December has 31 days");
			break;
			default: 
				System.out.println("Error month information");
		}
	}

}

　　运行结果：

please enter a number : 1~12
4
April has 30 days

　　方法二：随机产生1-12之间的某个整数：

package com.liaojianya.chapter1;
/**
 * This program demonstrates thw way of implements 
 * display the number of days according to 12 months.
 * @author LIAO JIANYA
 * 2016年7月19日
 */
public class MonthAndDays
{
	public static void main(String[] args)
	{
		int month = (int)(Math.random() * 12);
		System.out.println("随机产生一个月份并显示月份: " + month);
		switch (month)
		{
		case 1:
			System.out.println("January has 31 days");
			break;
		case 2:
			System.out.println("February has 28 days");
			break;
		case 3:
			System.out.println("March has 31 days");
			break;
		case 4:
			System.out.println("April has 30 days");
			break;
		case 5:
			System.out.println("May has 31 days");
			break;
		case 6:
			System.out.println("June has 30 days");
			break;
		case 7:
			System.out.println("July has 31 days");
			break;
		case 8:
			System.out.println("August has 31 days");
			break;
		case 9:
			System.out.println("September has 30 days");
			break;
		case 10:
			System.out.println("Octor has 31 days");
			break;
		case 11:
			System.out.println("November has 30 days");
			break;
		case 12:
			System.out.println("December has 31 days");
			break;
//			default: 
//				System.out.println("Error month information");
		}
	}

}

　　运行结果：

随机产生一个月份并显示月份: 3
March has 31 days

　　分析：随机产生月份时，default可以省略。

显示12个月各自全部的天数：

package com.liaojianya.chapter1;
/**
 * This program demonstrates the way of using array to storage days of each month.
 * @author LIAO JIANYA
 * 2016年7月19日
 */
public class ArrayDemo
{
	public static void main(String[] args)
	{
		int[] month = {31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31};
		for(int i = 0; i < month.length; i++)
		{
			System.out.println("第" + (i+1) + "月有" + month[i] + "天!");			
		}
	}

}

　　运行结果：

第1月有31天!
第2月有28天!
第3月有31天!
第4月有30天!
第5月有31天!
第6月有30天!
第7月有31天!
第8月有31天!
第9月有30天!
第10月有31天!
第11月有30天!
第12月有31天!