C++ 实现判断一个输入日期是星期几,是一年中的第几天


#include using namespace std; struct time { int year; int month; int day; unsigned int weekday; }; void initialtime(time & t); //输入初始化时间 void Show(time & t); //显示时间信息 int Weekdaycount(time & t); //计算当日是星期几 int Daycount(time & t); //计算当日是第公元多少天 int Daysyearcount(time & t); //计算当日是该年的第多少天 bool isleapyear(time & t); //判断该年是不是闰年 bool check(time &t); //检查时间格式是否正确int main() { time t; initialtime(t); Show(t); return 0; }bool check(time &t) { if (t.year <= 0 || (t.month <= 0 || t.month>12) || t.day <= 0) return false; else{ if ((t.month == 1 || t.month == 3 || t.month == 5 || t.month == 7 || t.month == 8 || t.month == 10 || t.month == 12) && t.day > 31)return false; else { if ((t.month == 4 || t.month == 6 || t.month == 9 || t.month == 11 ) && t.day > 30)return false; else { if (t.month == 2) { if (isleapyear(t)) { if (t.day > 29)return false; else return true; } else { if (t.day > 28)return false; else return true; } } } } } } void initialtime(time & t) { cout << "Enter the time (year,month,day):\n"; cin >> t.year; cin.get(); cin>> t.month; cin.get(); cin >> t.day; cin.get(); if (!check(t)){ cout << "Try again:\n"; initialtime(t); } else t.weekday = Weekdaycount(t); } void Show(time & t) { cout << "Year: " << t.year << "\t"; cout << "Month: " << t.month << "\t"; cout << "Day: " << t.day << "\t"; cout << "Weekday: " << t.weekday << endl; cout << "This is a "; if (isleapyear(t))cout << "leap"; else cout << "nonleap"; cout << " year.\n"; cout << "Today is the " << Daysyearcount(t) << " days of the year.\n"; } int Weekdaycount(time & t) { return Daycount(t) % 7; } int Daycount(time & t) { int days = 0; days = (t.year - 1) * 365 + (t.year - 1) / 4 - (t.year - 1) / 100 + (t.year - 1) / 400 + Daysyearcount(t); return days; } bool isleapyear(time & t) { if (t.year % 4 == 0 && t.year % 100 != 0) return true; //年是四的倍数而且不是100的倍数,是闰年 if (t.year % 400 == 0)return true; else return false; } int Daysyearcount(time & t) { int days = 0; int mtemp = t.month - 1; while (mtemp > 0) { switch (mtemp) { case(1) : case(3) : case(5) : case(7) : case(8) : case(10) : case(12) : days += 31; break; case(4): case(6): case(9): case(11): days += 30; break; case(2) : days += 28; break; default: break; } --mtemp; } if (isleapyear(t))++days; //如果是闰年,再加上一天 return days+t.day; //返回计算的天数加上当月的天数 }


以上是以独立函数实现的代码,下次改进用类的表达修改一下!

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