从日期开始计算一年中的哪一天 [英] Calculating day of year from date
本文介绍了从日期开始计算一年中的哪一天的处理方法,对大家解决问题具有一定的参考价值,需要的朋友们下面随着小编来一起学习吧!
问题描述
我需要计算给定日期的天数.一年有366天.但是,每个月都有一个不同的值,我必须指定这些值.有比我正在做的更快的方法吗?
I need to calculate the day number of a given date. The year has 366 days in it. Each month however has a different value and I have to assign the values. Is there a quicker way to do it rather than the way I am going about it?
#include<iostream>
using namespace std;
int main()
{
int day, month, year, dayNumber;
cout<< "Please enter the month, by numerical value:";
cin>> month;
cout<<"Please enter the day, by numerical value:";
cin>> day;
cout<<"Please enter the year, by numerical value:";
cin>> year;
if (month == 1)
{
dayNumber= day;
cout<< "Month;" << '\t'<< month << '\n'
<< "Day:"<<'\t'<< day<< '\n'
<< "Year:"<<'\t'<< year<<'\n'
<< "Day Number:"<< '\t'<< dayNumber<< endl;
}
else if(month==2)
{
dayNumber= day+31;
}
}
推荐答案
在许多方面,最好避免手动滚动.
In many ways it is probably best to avoid hand-rolling this.
使用增强功能:
#include <boost/date_time/gregorian/gregorian.hpp>
//...
try {
boost::gregorian::date d(year, month, day);
dayNumber = d.day_of_year();
}
catch (std::out_of_range& e) {
// Alternatively catch bad_year etc exceptions.
std::cout << "Bad date: " << e.what() << std::endl;
}
正如James Kanze建议的那样,您也可以使用mktime来避免依赖boost(未经测试):
As James Kanze suggests you could also use mktime to avoid dependency on boost (untested):
tm timeinfo = {};
timeinfo.tm_year = year - 1900;
timeinfo.tm_mon = month - 1;
timeinfo.tm_mday = day;
mktime(&timeinfo);
dayNumber = timeinfo.tm_yday;
这篇关于从日期开始计算一年中的哪一天的文章就介绍到这了,希望我们推荐的答案对大家有所帮助,也希望大家多多支持IT屋!
查看全文