c++的获取绝对秒函数的使用

利用绝对秒函数,可实现各种时间的加减运算,代码如下

unsigned  long  stime(int  year,  int  mon,int  day,  int  hour, int  min,  int  sec)  
{  
   if  (0  >=  (int)  (mon  -=  2))  {   /*  1..12  ->  11,12,1..10  */  
      mon  +=  12;    /*  Puts  Feb  last  since  it  has  leap  day  */  
      year  -=  1;  
   }  
   return  (((  
     (unsigned  long)(year/4  -  year/100  +  year/400  +  367*mon/12  +  day)  +  
      year*365  -  719499  
     )*24  +  hour  /*  now  have  hours  */  
    )*60  +  min  /*  now  have  minutes  */  
   )*60  +  sec;  /*  finally  seconds  */  
}

下面是利用这个函数所写的类:

//class.h
const char* WEEK[7+1] = {"","星期一","星期二","星期三","星期四","星期五","星期六","星期日"};

class Time
{
private:
	int day;
	int month;
	int year;
	int week;
public:
	Time(int d = 0, int m = 0, int y = 0):day(d),month(m),year(y){}
	
	//返回当前天的星期
	const char* getthisday(){return WEEK[week];}	
	long operator - (Time& t);
	
	//friend
	friend std::istream& operator >> (std::istream& is, Time& t);		//输入
	friend std::ostream& operator << (std::ostream& os, const Time& t);	//输出
};
std::istream& operator >> (std::istream& is, Time& t)
{
	is >> t.year >> t.month  >> t.day;	
	
	//转载星期算法
	t.week = ( t.day + 2*t.month + 3*(t.month+1)/5 + t.year + t.year/4 - t.year/100 + t.year/400) % 7+1;   

	return is;
}
std::ostream& operator << (std::ostream& os, const Time& t)
{
	os << t.year << "-" << t.month << "-" << t.day << "-" << WEEK[t.week];
	return os;
}
long Time::operator - (Time& t)
{
	unsigned long a = stime(year, month, day, 0, 0, 0);
	unsigned long b = stime(t.year, t.month, t.day, 0, 0, 0);

	return (a>b)?(a-b)/(3600*24):(b-a)/(3600*24);
}

main函数:

#include <iostream>
#include "class.h"

using std::cin;
using std::cout;
using std::endl;

int main()
{
	Time a,b;
	cout << "输入第一个日期(年/月/日): ";
	cin >> a;
	cout << "输入第二个日期(年/月/日): ";
	cin >> b;

	//实现星期的计算
	cout << a << endl;
	cout << b << endl;

	//实现天数差计算
	cout << "两个日期间隔: " << a-b << "天" << endl;

	cin.get();
	cin.get();

	return 0;
}

程序演示: