programming-examples/c++/Others/Forever Calender in C++.cpp

Forever Calender in C++

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

int step1 (int);
void month_name(int);
int no_days(int,int);
int leap(int);

void main()
{
 restart:
 clrscr();
 cout<<"Enter year : ";
 unsigned int y,m;
 cin>>y;
 int x;
 x=step1(y);
 int month[14][12]= {1,4,4,7,2,5,7,3,6,1,4,6,
		     2,5,5,1,3,6,1,4,7,2,5,7,
		     3,6,6,2,4,7,2,5,1,3,6,1,
		     4,7,7,3,5,1,3,6,2,4,7,2,
		     5,1,1,4,6,2,4,7,3,5,1,3,
		     6,2,2,5,7,3,5,1,4,6,2,4,
		     7,3,3,6,1,4,6,2,5,7,3,5,
		     1,4,5,1,3,6,1,4,7,2,5,7,
		     2,5,6,2,4,7,2,5,1,3,6,1,
		     3,6,7,3,5,1,3,6,2,4,7,2,
		     4,7,1,4,6,2,4,7,3,5,1,3,
		     5,1,2,5,7,3,5,1,4,6,2,4,
		     6,2,3,6,1,4,6,2,5,7,3,5,
		     7,3,4,7,2,5,7,3,6,1,4,6};
 cout<<"Enter month (1 - 12) : ";
 month_input:
 cin>>m;
 if(m<1 || m>12)
 {
  cout<<"Enter a valid month (1 - 12) : ";
  goto month_input;
 }
 cout<<"

		";
 month_name(m);
 cout<<' '<<y<<"

Mon	Tue	Wed	Thu	Fri	Sat	Sun
";
 int j=month[x-1][m-1], days=no_days(m,y);
 for (int i=0; i<j-1; i++)
  cout<<'	';
 for(i=1; i<=days; i++)
 {
  cout<<i<<'	';
  if(j==7)
  {
   cout<<'
';
   j=1;
  }
  else
   j++;
 }
 cout<<"

Try for another month? (y/n) : ";
 char ch;
 cin>>ch;
 if(ch=='y' || ch=='Y')
  goto restart;
}
int step1 (int y)
{
 int x=y%7;
 x+=(y-1)/4;
 x-=(y-1)/100;
 x+=(y-1)/400;
 x=x%7;
 if(x==0)
  x=7;
 if(leap(y))
  x+=7;
 return x;
}
void month_name(int m)
{
 switch(m)
 {
  case 1 : cout<<"January";
	break;
  case 2 : cout<<"February";
	break;
  case 3 : cout<<"March";
	break;
  case 4 : cout<<"April";
	break;
  case 5 : cout<<"May";
	break;
  case 6 : cout<<"June";
	break;
  case 7 : cout<<"July";
	break;
  case 8 : cout<<"August";
	break;
  case 9 : cout<<"September";
	break;
  case 10: cout<<"October";
	break;
  case 11: cout<<"November";
	break;
  case 12: cout<<"December";
	break;
 }
}

int no_days(int mon, int y)
{
 int d;
 switch(mon)
 {
  case 1 :
  case 3 :
  case 5 :
  case 7 :
  case 8 :
  case 10:
  case 12: d=31;
	   break;
  case 4 :
  case 6 :
  case 9 :
  case 11: d=30;
	   break;
  case 2 : if(leap(y))
	    d=29;
	   else
	    d=28;
	   break;
 }
 return d;
}
int leap (int y)
{
 if (y%100==0)
  if (y%400==0)
   return 1;
  else
   return 0;
 else
  if (y%4==0)
   return 1;
  else
   return 0;
}