C++ 编程练习1

1. 编写日历打印程序，要求实现如下的main函数：

    class Calendar;

    int main() {

        Calendar c0;

        Calendar c1(2013);

        Calendar c2(2013, 4);

        Calendar c3(2013, 4, 23);

 

        cout<<c0<<c1<<c2<<c3;

        c0 = c3;

        cout<<c0;

    }

[Accepted 2013/0504]

#ifndef _CALENDAR_H_#define _CALENDAR_H_#include <iostream>using namespace std;class Year{public:Year(int y = -1){year = y;}~Year(){}void print(ostream& out)const ;protected:int year;bool is_leap_year()const ;int cal_1st_day()const ;};class Month: public Year{public:Month(int y = -1, int m = -1): Year(y){month = m;}~Month() {}void print(ostream& out)const ;protected:int month;int cal_1st_day()const ;};class Day: public Month{private:int day;int calculate()const ;public:Day(int y = -1, int m = -1, int d = -1): Month(y, m) {day = d;}~Day() {}void print(ostream& out)const ;};class Calendar{private:int year;int month;int day;public:Calendar(int y = 1, int m = -1, int d = -1) {year = y;month = m;day = d;}void print(ostream& out)const {if(month == -1 && day == -1){Year a(year);a.print(out);}if(month != -1 && day == -1){Month a(year, month);a.print(out);}if(month != -1 && day != -1){Day a(year, month , day);a.print(out);}}Calendar& operator=(const Calendar& src){year = src.year;month = src.month;day = src.day;return (*this);}};#endif

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#include "calendar.h"bool Year::is_leap_year()const {if (year % 400 == 0 || year % 100 != 0 && year % 4 == 0)return true;else return false;}int Year::cal_1st_day()const {int num_leap_year = 0;int first_day = 0;num_leap_year = (year - 1) / 4 + (year - 1) / 400 - (year - 1) / 100;first_day = ( year + num_leap_year) % 7;return first_day;}void Day::print(ostream& out)const {const char* days[7] = {"Sunday", "Monday", "Tuesday", "Wednesday", "Thurday", "Friday", "Saturday"};int day_of_week = 0;day_of_week = calculate();out<<year<<"."<<month<<"."<<day<<" is "<<days[day_of_week]<<endl;}void Month::print(ostream& out)const {int first_day_of_month = 0;int months[13] = {0, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31,30, 31};const char* days[7] = {"Sunday", "Monday", "Tuesday", "Wednesday", "Thurday", "Friday", "Saturday"};if(is_leap_year())  months[2] = 29;first_day_of_month = cal_1st_day();out<<month<<endl;for(int i = 0; i < 7; i++) {     out.width(10);out<<days[i];}out<<endl;for(int i = 0; i < first_day_of_month; i++) {    out.width(10);   out<<" ";}for(int i = 1; i < months[month] + 1; i++){out.width(10);out<<i;if((first_day_of_month + i) % 7 == 0)  out<<endl;}}void Year::print(std::ostream& out)const {out<<"The calendar of "<<year<<endl;for(int i = 1; i < 13; i++){Month month(year, i);month.print(out);cout<<endl;}}int Month::cal_1st_day()const {int first_day_of_year = 0;int first_day_of_month = 0;int months[13] = {0, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31,30, 31};first_day_of_year = Year::cal_1st_day();if(is_leap_year())   months[2] = 29;first_day_of_month = first_day_of_year;for(int i = 1; i < month; i++){first_day_of_month += months[i] % 7;}return first_day_of_month % 7;}int Day::calculate()const {int first_day_of_month = 0;first_day_of_month = Month::cal_1st_day();return (first_day_of_month + day - 1) %7;}

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#include "calendar.h"ostream& operator<<(ostream& out, const Calendar& obj){obj.print(out);return out;}int main(){    Calendar c0;    //Calendar c0(1);    Calendar c1(2013);    Calendar c2(2013, 5);    Calendar c3(2013, 5, 4);    cout<<c0<<c1<<c2<<c3;c1 = c2 = c3;cout<<c1<<c2<<c3;c3 = c0;            c0 = c3;         cout<<c0;return 0;}