C++实现万年历小功能

#include
#include
#include
using namespace std;
int number;       //菜单键
int year, month, day;   //年、月、日
int i, j, t;       //for循环用的量
int s;          //星期X
char c;         //存放随机输入的数字，以实现“按任意键返回主菜单”的功能
char months[] = { 0,31,28,31,30,31,30,31,31,30,31,30,31 };   //平年每个月的天数
 
void Pos(int x, int y);   //光标位置
void menu();        //主菜单函数
void runnian();       //如是闰年则变第二个月天数28为29
void oneyear();       //输出一整年的年历
void onemonth();      //输出一个月的月历
void xianshiweek();     //显示星期数
 
void Pos(int x, int y)//光标位置 
{
 COORD pos;
 HANDLE hOutput;
 pos.X = x;
 pos.Y = y;
 hOutput = GetStdHandle(STD_OUTPUT_HANDLE);
 SetConsoleCursorPosition(hOutput, pos);
}
void menu()//主菜单函数
{
 Pos(40, 3);
 cout <<"***********************************" <> number;
 if (number <0 || number>3)
 {
 system("cls");
 Pos(20, 15);
 cout <<"输入数字无效,请重新输入!" <> year;
 if ((year % 4 == 0 && year % 100 != 0) || (year % 400 == 0))   //闰年判断公式
 {
 months[2] = 29;
 }
}
void oneyear()   //输出一整年的年历
{
 cout <<"请输入年份：";
 runnian();
 system("cls");   //清屏
 cout <<"请输入年份：" <> c;
 system("cls");
 menu();
}
void onemonth()//输出一个月的月历
{
 int s = 0;
 cout <<"请输入年份：";
 runnian();
 cout <<"请输入月份：";
 cin >> month;
 system("cls");
 cout <<"请输入年份：" <> c;
 system("cls");
 menu();
}
void xianshiweek()   //显示星期数
{
 int s = 0;
 cout <<"请输入年份：";
 runnian();
 cout <<"请输入月份：";
 cin >> month;
 cout <<"请输入日期：";
 cin >> day;
 system("cls");
 cout <<"请输入年份：" <> c;
 system("cls");
 menu();
}
int main()//主函数
{
 setlocale(LC_ALL, "chs");//转中文
 menu();
 while (number != 0)
 {
 switch (number)
 {
 case 1:
 {
  oneyear();
  break;
 }
 case 2:
 {
  onemonth();
  break;
 }
 case 3:
 {
  xianshiweek();
  break;
 }
 }
 months[2] = 28; //把months[2]变为初值
 }
 if (number == 0)
 {
 system("pause");
 }
 return 0;
}