任何和日期相关的函数都在这里<<0922
与日期相关的函数汇总
#include "Date.h"//头文件里面不要放置命名空间
#include <stdio.h>
#include <stdlib.h>
#include <time.h>
using namespace std;
const int Date::kDaysOfMonth[2][12] = //类里面的static变量,存储着所有的类对象都可以使用的变量
{
{31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31},
{31, 29, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31}
};
const string Date::kNameOfMonth[12] = //类外面定义private里面的static变量
{
"January", "February", "March", "April", "May", "June", "July",
"August", "September", "October", "November", "December"
};
Date::Date()
:year_(0),
month_(0),
day_(0)
{
}
Date::Date(int year,
int month,
int day)
:year_(year),
month_(month),
day_(day)
{
}
bool Date::isLeapYear() const
{
return (year_%4 == 0 && year_%100 != 0) || year_%400 == 0;//在类外面定义的类函数,可以直接操作类里面的元素
}
bool Date::isValid() const
{
return year_ > 0
&& month_ > 0
&& month_ <= 12
&& day_ > 0
&& day_ <= kDaysOfMonth[isLeapYear()][month_-1];
}
void Date::assertValid() const//标准的判断输入是否为合法的函数表达
{
if(!isValid())
abort();
}
int Date::calDaysOfYear() const
{
assertValid();
int leap = isLeapYear();
int result = 0;
for(int i = 1; i < month_; ++i)
{
result += kDaysOfMonth[leap][i-1];//这种方式,利用建立两个数组的方式省去了关于月份是否小于2的判断
}
result += day_;
return result;
}
int Date::calLeftDaysOfYear() const
{
bool leap = isLeapYear();
int days = calDaysOfYear();
if(leap == true)
return 366 - days;
else
return 365 - days;
}
int Date::compareDate(const Date &other) const //供diff函数使用
{
assertValid();
other.assertValid();
int res = year_ - other.year_;
if(res == 0)
res = month_ - other.month_;
if(res == 0)
res = day_ - other.day_;
return res;
}
void Date::setDate(int year, int month, int day)
{
year_ = year;
month_ = month;
day_ = day;
}
void Date::setToday()
{
time_t t = time(NULL);
struct tm *pt = localtime(&t);//localtime函数获取tm结构体,而timeval结构体里面存的是获取当前时间戳
if(pt == NULL)
{
perror("localtime");
exit(EXIT_FAILURE);
}
year_ = pt->tm_year + 1900;
month_ = pt->tm_mon + 1;
day_ = pt->tm_mday;
}
string Date::toString() const
{
assertValid();
//2009 7/31
char text[100] = {0};
snprintf(text, sizeof text, "%04d %02d %02d", year_, month_, day_);
return string(text);
}
string Date::toFormatString() const
{
assertValid();
//22 September 2014
char text[1024] = {0};
snprintf(text, sizeof text, "%d %s %04d", day_, kNameOfMonth[month_-1].c_str(), year_);
return string(text);
}
int Date::differenceDate(const Date &d1, const Date &d2)
{
Date t1, t2; //t1 < t2
bool minus = false;
int days = 0;
int diff = d1.compareDate(d2);//使用一个diff函数,在算日期的时候,实现小日期在前面!!
if(diff == 0)
return 0;
else if(diff < 0) //d1 < d2
{
t1 = d1;
t2 = d2;
minus = true;
}
else if(diff > 0)
{
t1 = d2;
t2 = d1;
minus = false;
}
//只需比较t1与t2
//这里保证t1 < t2
//只需计算出天数的差距
if(t1.year_ == t2.year_) //同一年
days = t2.calDaysOfYear() - t1.calDaysOfYear();
else
{
days += t1.calLeftDaysOfYear(); //t1剩余的天数
for(int i = t1.year_+1; i <= t2.year_-1 ; ++i)
{
bool leap = (i%4 == 0 && i%100 != 0) || i%400 == 0;
days += (leap == true ? 366 : 365);
}
days += t2.calDaysOfYear(); //t2的天数
}
if(minus == true)
return -1 * days;
else
return days;
}
#include "Date.h"
#include <iostream>
#include <string>
#include <vector>
#include <assert.h>//调用assert的头文件
using namespace std;
int main(int argc, const char *argv[])
{
Date d;
assert(!d.isValid());//assert的使用场景:判断类是否为空!
d.setToday();
cout << "Today : " << d.toString() << endl;
cout << "Today Format : " << d.toFormatString() << endl;
cout << "今天是2014年的第 " << d.calDaysOfYear() << "天" << endl;
cout << "今年还剩 " << d.calLeftDaysOfYear() << "天" << endl;
Date d2(1993, 6, 27);
cout << Date::differenceDate(d, d2) << endl;
return 0;
}
posted on 2014-09-24 00:59 __hello world 阅读(121) 评论(0) 编辑 收藏 举报