用C++写简易日历

用c++制作的简易日历 包括4个功能

#include<iostream>
#include<stdlib.h>
#include<iomanip>
using namespace std;
int o;
bool prime = 1;
bool prime1 = 1;
bool prime2 = 1;
struct {
	int year;
	int month;
	int day;
}date;
int main()
{
	void op1();
	void op2();
	void op3();
	void op4();
	void op5();
	
	cout << "1.显示某一年的全年日历\n";
	cout << "2.显示某年某月的月历\n";
	cout << "3.显示某年某月某日是星期几\n";
	cout << "4.显示某年某月某日是该年度的第几天\n";
	cout << "5.退出\n";
	int z;
	cout << "请选择(0-4)" << endl;
	cin >> z;
	switch (z)
	{
	case 1: op1(); 
		break;
	case 2: op2(); 
		break;
	case 3: op3(); 
		break;
	case 4: op4(); 
		break;
	case 5: op5(); 
		break;
	}

	return 0;
}
void op4()
{
	int days;
	cout << "输入年月日" << endl;
	cin >> date.year >> date.month >> date.day;
	switch (date.month)
	{
	case 1:days = date.day; 
		break;
	case 2:days = date.day + 31; 
		break;
	case 3:days = date.day + 59; 
		break;
	case 4:days = date.day + 90; 
		break;
	case 5:days = date.day + 120; 
		break;
	case 6:days = date.day + 151; 
		break;
	case 7:days = date.day + 181; 
		break;
	case 8:days =date.day + 212; 
		break;
	case 9:days = date.day + 243; 
		break;
	case 10:days = date.day + 273; 
		break;
	case 11:days = date.day + 304;
		break;
	case 12:days = date.day + 334; 
		break;
	}
	cout << date.year << "年" << date.month << "月" << date.day << "日是本年度的第" << days << "天" << endl;
}
void op3()
{
	int xq, d1;
	if (prime)
	{
		cout << "输入年份" << endl;
		cin >> date.year;
		cout << "输入本月份" << endl;
		cin >> date.month;
		cout << "输入日份" << endl;
		cin >> date.day;
	}
	else if (prime1)
	{
		cout << "输入年份" << endl;
		cin >> date.year;
		cout << "输入本月份" << endl;
		cin >> date.month;
		date.day = 1;
	}
	else if (prime2)
	{
		cout << "输入年份" << endl;
		cin >> date.year;
	}
	d1 = (date.year - 1) * 365 + (date.year - 1) / 4 - (date.year / 100) + (date.year / 400);//百度搜的公式
	xq = d1 % 7 + 1;
	switch (date.month)
	{
	case 1:date.day = date.day; break;
	case 2:date.day = date.day + 31; break;
	case 3:date.day = date.day + 59; break;
	case 4:date.day = date.day + 90; break;
	case 5:date.day = date.day + 120; break;
	case 6:date.day = date.day + 151; break;
	case 7:date.day = date.day + 181; break;
	case 8:date.day = date.day + 212; break;
	case 9:date.day = date.day + 243; break;
	case 10:date.day = date.day + 273; break;
	case 11:date.day = date.day + 304; break;
	case 12:date.day = date.day + 334; break;
	}

	if (((date.year % 4 == 0 && date.year % 100 != 0) || date.year % 400 == 0) && date.month >= 3)//判断闰年
		date.day += 1;
	xq = (xq + (date.day - 1)) % 7;
	if (xq == 0) xq = 7;
	if (prime)
	switch (xq)
	{
	case 1:cout << "该天是星期一" << endl; break;
	case 2:cout << "该天是星期二" << endl; break;
	case 3:cout << "该天是星期三" << endl; break;
	case 4:cout << "该天是星期四" << endl; break;
	case 5:cout << "该天是星期五" << endl; break;
	case 6:cout << "该天是星期六" << endl; break;
	case 7:cout << "该天是星期日" << endl; break;
	}
}
void op2()
{
	prime = 0;
	op3();
	int i, s;
	int a[13] = { 0,31,28,31,30,31,30,31,31,30,31,30,31 };
	int m = 0, b = 0;
	if ((date.year % 4 == 0 && date.year % 100 != 0) || date.year % 400 == 0) a[2] = 29;
	cout << date.year << "年" << date.month << "月" << endl;
	i = date.month;
	cout << "------------------------------------------" << endl;
	cout << "    日    一    二    三    四    五    六" << endl;
	cout << "------------------------------------------" << endl;
	if (o == 7) o = 0;

	for (m = 0; m < o; m++) cout << "      ";
	for (b = 1; b <= a[i]; b++)
	{
		cout << setw(6) << b;
		if ((b + o) % 7 == 0) cout << endl;
	}
	if (b < 33) cout << endl;

	for (m = 0; m < o; m++) cout << " " << endl;
	prime = 0;
}
void op1()
{
	prime1 = 0;
	for (date.month = 1; date.month <= 12; date.month++)
	{
         op2();
		prime2 = 0;
	}
}
void op5()
{
	cout << "byebye\n";
}