今天看到一个很有意思的话题,例的标题叙述性描述,下面:
根据以下信息来计算1901年1月1至2000年12月31适逢星期日每个月的第一天的合伙人数量?
a) 1900.1.1星期一
b) 1月,3月。5月。7月,8月,10月和12月是31天
c) 4月,6月。9月和11月是30天
d) 2月是28天,在闰年是29天
e) 公元年数能被4整除且又不能被100整除是闰年
f) 能直接被400整除也是闰年
下面是C语言实现版本号:
#include <stdio.h> #include <stdbool.h> bool isLeapYear(int year); // start is the weekday of 1st, January // return the num of the first day of each month // is Sunday. // the start will change into the next year int getYearNum(int* start, int year); // Num of days of each month int days[13] = {0, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31}; int leapdays[13] = {0, 31, 29, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31}; int main(void) { int sum = 0; int start = 1901; int end = 2000; int startWeek = 1; int startYear = 1900; int i; for (i = 1; i < 13; ++i) days[i] += days[i - 1]; for (i = 1; i < 13; ++i) leapdays[i] += leapdays[i - 1]; for (i = startYear; i < start; ++i) getYearNum(&startWeek, i); for (i = start; i <= end; ++i) sum += getYearNum(&startWeek, i); printf("%d ", sum); return 0; } bool isLeapYear(int year) { if (year % 4 == 0 && year % 100 != 0) return true; else if (year % 400 == 0) return true; return false; } int getYearNum(int* start, int year) { int i; int count = 0; int yeardays; if (isLeapYear(year)) { yeardays = 366; for (i = 0; i < 12; ++i) if ((leapdays[i] % 7 + *start)%7 == 0) ++count; } else { yeardays = 365; for (i = 0; i < 12; ++i) if ((days[i] % 7 + *start)%7 == 0) ++count; } *start = (yeardays % 7 + *start)%7; return count; }
以下是强大的C++和boost程序库的舞台:
#include <boost/date_time/gregorian/gregorian.hpp> #include <iostream> using namespace std; using namespace boost::gregorian; int main() { int startYear, endYear; cout << "Please input the start year: "; cin >> startYear; cout << "Please input the end year: "; cin >> endYear; date stdt(startYear, 1, 1); date eddt(endYear + 1, 1, 1); month_iterator m_iter(stdt); int sum = 0; while (m_iter != eddt) { if (m_iter->day_of_week() == 0) { cout << *m_iter << " is Sunday" << endl; ++sum; } ++m_iter; } cout << "There are " << sum << " Sundays are the 1st day of month between " << stdt << " and " << eddt - date_duration(1) << endl; return 0; }
效果例如以下:
下来是最简单的python:
import calendar sum = 0 startYear = 1901 endYear = 2000 for year in xrange(startYear, endYear + 1): for month in xrange(1, 13): if calendar.monthcalendar(year, month)[0].index(1) == 6: sum = sum + 1 print sum
近期对于JavaScript的网页脚本有点感兴趣。就试着用JavaScript实现了一下,感觉不错,有可视化和跨平台性:
function main() { var myDate = new Date(); var startYear = document.getElementById("startText").value; var endYear = document.getElementById("endText").value; var sum = 0; var result = document.getElementById("resultText"); result.innerHTML = ""; myDate.setDate(1); for (var year = startYear; year <= endYear; year++) { myDate.setFullYear(year); for (var month = 0; month < 12; month++) { myDate.setMonth(month); if (myDate.getDay() == 0) { /*var newDate = document.createElement("p"); newDate.innerHTML = myDate.toString(); result.appendChild(newDate);*/ result.innerHTML += myDate.toDateString() + "<br/>"; sum++; } } } myDate.setFullYear(startYear); myDate.setMonth(0); myDate.setDate(1); result.innerHTML += "<br/>There are " + sum + " Sundays are the 1st day of month between " + myDate.toDateString(); myDate.setFullYear(endYear); myDate.setMonth(11); myDate.setDate(31); result.innerHTML += " and " + myDate.toDateString(); }
相应的HTML
<!DOCTYPE html> <html lang="zh-cn"> <head> <meta charset="UTF-8"> <meta name="viewport" content="width=device-width, initial-scale=1"> <title>Question 2</title> <script src="test.js" type="text/javascript"></script> </head> <body> 请输入起始年份: <input type="text" id="startText" autofocus onkeydown="if(event.keyCode==13){endText.focus();}"/> <br/> 请输入终止年份: <input type="text" id="endText" onkeydown="if(event.keyCode==13){ok.click();}"/> <br/> <button id="ok" onclick="main()"> 确定 </button> <div id="resultText"> </body> </html>
效果例如以下
再看很严谨的Java程序:
import java.util.Calendar; import java.util.Scanner; import java.text.SimpleDateFormat; public class Question2 { static public void main(String[] args) { int startYear, endYear; Scanner sc = new Scanner(System.in); System.out.print("Please input start year: "); startYear = sc.nextInt(); System.out.print("Please input end year: "); endYear = sc.nextInt(); int sum = 0; Calendar dt = Calendar.getInstance(); SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd"); for (int year = startYear; year <= endYear; ++year) { dt.set(Calendar.YEAR, year); for (int month = 1; month < 13; ++month) { dt.set(Calendar.MONTH, month); dt.set(Calendar.DAY_OF_MONTH, 1); if (dt.get(Calendar.DAY_OF_WEEK) == Calendar.SUNDAY) { System.out.println(sdf.format(dt.getTime()) + " is Sunday."); ++sum; } } } dt.set(startYear, Calendar.JANUARY, 1); System.out.print("There are " + sum + " Sundays are the 1st day of month between " + sdf.format(dt.getTime())); dt.set(endYear, Calendar.DECEMBER, 31); System.out.println(" to " + sdf.format(dt.getTime())); } }
执行效果例如以下:
最后的最后,来一个鬼畜版:Matlab版本号:
startYear = input('Please input the start year: '); endYear = input('Please input the end year: '); sum = 0; for year = startYear : endYear for month = 1 : 12 cal = calendar(year, month); if cal(1,1) == 1 sum = sum + 1; display([num2str(year) '-' num2str(month) '-1 is Sunday']); end end end display(['There are ' num2str(sum) ... ' Sundays are the 1st day of month between ' num2str(startYear)... '-1-1 to ' num2str(endYear) '-1-1']);
效果为:
OK,一个问题,多种语言。的优点和缺点。同时多国语言是一个很好的经验。