【王道JAVA】【程序 14 求日期】

题目：输入某年某月某日，判断这一天是这一年的第几天？
程序分析：以 3 月 5 日为例，应该先把前两个月的加起来，然后再加上 5 天即本年的第几天，特殊情况，闰年且输入月份大于 3 时需考虑多加一天。

import java.util.Scanner;

public class WangDao {
	public static void main(String[] args) {
		Scanner scan = new Scanner(System.in);
		System.out.print("Enter year: ");
		int year = scan.nextInt();
		System.out.print("Enter month: ");
		int month = scan.nextInt();
		System.out.print("Enter day: ");
		int day = scan.nextInt();
		
		int[][] arr = {{0, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31},
					   {0, 31, 29, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31}};
		int x = 0, whichDay = 0;
		if (isLeapYear(year)) {
			x = 1;
		} else {
			x = 0;
		}
		for (int i = 1; i < month; i++) {
			whichDay += arr[x][i];
		}
		whichDay += day;
		System.out.println("This day is the " + whichDay + "th day of the year.");
	}
	public static boolean isLeapYear(int n) {
		boolean flag = false;
		
		if ((n % 400 == 0) || (n % 100 != 0 && n % 4 == 0)) {
			flag = true;
		}
		
		return flag;
	}
}