如何用c++编写万年历

要求：模仿现实生活中的挂历.
当前页以系统当前日期的月份为准显示当前月的每一天(显示出日及对应的星期几).
当系统日期变到下一月时，系统自动翻页到下一月.
就是运行这个cpp他就自动显示当前系统日期，然后到下一个月会自动翻页

// WNL.cpp : 定义控制台应用程序的入口点。
//

#include "stdafx.h"

#include<iostream>
#include<stdlib.h>
#include<conio.h>


using namespace std;
char Content();
int Distinguish(int year, int month);
int DayNum(int year, int month);
void  OutPut(int days, int year, int month);

int main()
{
    int year = 0, month = 0;
    char select;//用char记录选择
    l:cout << "！欢迎使用万年历！" << endl;
    cout << "please input the year and  month you want to see:";
    cin >> year;
    cin >> month;
    OutPut(DayNum(year, month), year, month);
    m:select = Content();//将返回的字符接收
    switch (select)
    {
        case '>':
        month = month + 1;
        if (month >= 13)
        {
            year = year + 1;
            month = month % 12;
        }
        system("cls"); 
        cout << year << "年" << month << "月\n";
        OutPut(DayNum(year, month), year, month);
        goto m;
        case '<':
        month = month - 1;
        if (month <= 0)
        {
            year = year - 1;
            month = month + 12;
        }
        system("cls"); 
        cout << year << "年" << month << "月\n";
        OutPut(DayNum(year, month), year, month);
        goto m;

        case '?':
           system("cls"); //清屏
        goto l;
        case '#':
           system("cls");
           cout << "已退出,谢谢使用！" << endl;
        break;
    }
    return 0;
}
int Distinguish(int year, int month)
{
    int days = 0;
    if (year % 400 == 0 || (year % 4 == 0 && year % 100 != 0))
    {
        if (month == 2)
        {
            days = 29;
        }
        else if (month == 4 || month == 6 || month == 9 || month == 11)
        {
            days = 30;
        }
        else if (month == 1 || month == 3 || month == 5 || month == 7 || month == 8 || month == 10 || month == 12)
        {
            days = 31;
        }
    }
    else
    {
        if (month == 2)
        {
            days = 28;
        }
        else if (month == 4 || month == 6 || month == 9 || month == 11)
        {
            days = 30;
        }
        else if (month == 1 || month == 3 || month == 5 || month == 7 || month == 8 || month == 10 || month == 12)
        {
            days = 31;
        }
    }
    return days;
}

char Content()
{
    char select;
    cout << "$$$$$$$$$$$$$$$$$$$$$$$$$$$$" << endl;
    cout << "$$$$$$$ > nest month $$$$$$$" << endl;
    cout << "$$$$$$$ < last month $$$$$$$" << endl;
    cout << "$$$$$$$ ? resert date $$$$$$" << endl;
    cout << "$$$$$$$$$$ # quit $$$$$$$$$$" << endl;
    cout << "$$$$$$$$$$$$$$$$$$$$$$$$$$$$" << endl;
    cout << "Please input your select: ";
    cin >> select;
    return select;
}

int DayNum(int year, int month)
{
    int days = 0;
    int pingyear = 0, runyear = 0;
    for (int i = 1; i <= year - 1; i++)
    {
        if ((i % 4 == 0 && i % 100 != 0) || i % 400 == 0)
        {
            runyear++;
        }
    }
    pingyear = year - 1 - runyear;//记得减1，因为我们计算的是全年到元年的整天数
    days = pingyear * 365 + runyear * 366;
    for (int i = 1; i <= month - 1; i++)//再加上输入的年的零散的几个月的天数
    {
        days += Distinguish(year, i);
    }
    return days;
}

void  OutPut(int days, int year, int month)
{
    int i, k = 0, n;
    cout << "日" << '\t' << "一" << '\t' << "二" << '\t' << "三" << '\t' << "四" << '\t' << "五" << '\t' << "六" << '\t' << endl;
    cout << "~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~" << endl;
    k = days % 7;
    if (k != 6)//表示第一行开头需要有k+1个空，k+1表示上个月所占空位置数。
    {
        for (i = 0; i < k + 1; i++)
            cout << ' ' << '\t';
    }
    k = k + 1 + 1;//调整k值，用于接下来的输出计数。此时，k代表下一个要输出的位置
    n = Distinguish(year, month);
    for (i = 1; i <= n; i++)
    {
        cout << i << '\t';
        if (k % 7 == 0) //每行七个
        {
            cout << endl;
        }
        k = k + 1;
    }
    cout << endl;
}

可以参考：

C++编写电子万年历系统_依德子龙的博客-CSDN博客_c++电子日历 #include <iostream>#include <conio.h>#include<cstdlib>#include<string>#include<iomanip>using namespace std;int month_days[13] = {0, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31}; //定义全局数组//函数声明int leaptear(int n);//. https://blog.csdn.net/w73060815/article/details/122280389

#include<iostream>
#include<stdlib.h>
#include<conio.h>
using namespace std;
char Content();//打印菜单
int Distinguish(int year, int month);/*判断月份的类型，确定此月的天数*/
int DayNum(int year, int month);// 计算从公元1月1日到所输入的时间的前一个月的最后一天的总天数
void  OutPut(int days, int year, int month);
int main()
{
int year = 0, month = 0;
char select;//用char记录选择
l:cout << "！欢迎使用万年历！" << endl;
cout << "please input the year and  month you want to see:";
cin >> year;
cin >> month;
OutPut(DayNum(year, month), year, month);
m:select = Content();//将返回的字符接收
switch (select)
{
case '>':

month = month + 1;
if (month >= 13)
{
year = year + 1;
month = month % 12;
}
system("cls"); //清屏
cout << year << "年" << month << "月
";
OutPut(DayNum(year, month), year, month);
goto m;//18行定义
case '<':
month = month - 1;
if (month <= 0)
{
year = year - 1;
month = month + 12;
}
system("cls"); //清屏
cout << year << "年" << month << "月
";
OutPut(DayNum(year, month), year, month);
goto m;//18行定义
case '?':
system("cls"); //清屏
goto l;
case '#':
system("cls");
cout << "已退出,谢谢使用！" << endl;
break;
}
return 0;
}
int Distinguish(int year, int month)//判断并返回所查月份的天数
{
int days = 0;
if (year % 400 == 0 || (year % 4 == 0 && year % 100 != 0))
{
if (month == 2)
{
days = 29;
}
else if (month == 4 || month == 6 || month == 9 || month == 11)
{
days = 30;
}
else if (month == 1 || month == 3 || month == 5 || month == 7 || month == 8 || month == 10 || month == 12)
{
days = 31;
}
}
else
{
if (month == 2)
{
days = 28;
}
else if (month == 4 || month == 6 || month == 9 || month == 11)
{
days = 30;
}
else if (month == 1 || month == 3 || month == 5 || month == 7 || month == 8 || month == 10 || month == 12)
{
days = 31;
}
}
return days;
}

char Content()
{
char select;
cout << "$$$$$$$$$$$$$$$$$$$$$$$$$$$$" << endl;
cout << "$$$$$$$ > nest month $$$$$$$" << endl;
cout << "$$$$$$$ < last month $$$$$$$" << endl;
cout << "$$$$$$$ ? resert date $$$$$$" << endl;
cout << "$$$$$$$$$$ # quit $$$$$$$$$$" << endl;
cout << "$$$$$$$$$$$$$$$$$$$$$$$$$$$$" << endl;
cout << "Please input your select: ";
cin >> select;
return select;
}

int DayNum(int year, int month)
{
int days = 0;
int pingyear = 0, runyear = 0;
for (int i = 1; i <= year - 1; i++)
{
if ((i % 4 == 0 && i % 100 != 0) || i % 400 == 0)
{
runyear++;
}
}
pingyear = year - 1 - runyear;//记得减1，因为我们计算的是全年到元年的整天数
days = pingyear * 365 + runyear * 366;
for (int i = 1; i <= month - 1; i++)//再加上输入的年的零散的几个月的天数
{
days += Distinguish(year, i);
}
return days;
}

void  OutPut(int days, int year, int month)
{
int i, k = 0, n;
cout << "日" << '    ' << "一" << '    ' << "二" << '    ' << "三" << '    ' << "四" << '    ' << "五" << '    ' << "六" << '    ' << endl;
cout << "~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~" << endl;
k = days % 7;
if (k != 6)//表示第一行开头需要有k+1个空，k+1表示上个月所占空位置数。
{
for (i = 0; i < k + 1; i++)
cout << ' ' << '    ';
}
k = k + 1 + 1;//调整k值，用于接下来的输出计数。此时，k代表下一个要输出的位置
n = Distinguish(year, month);
for (i = 1; i <= n; i++)
{
cout << i << '    ';
if (k % 7 == 0) //每行七个
{
cout << endl;
}
k = k + 1;
}
cout << endl;
}