date.cc

this is a lp0 compilator new

/***********************************************************************
   Gerald Carter
   cse 525
   Spring 1994
   date.cc 
   
   DESCRIPTION : This file contains the class method definitions for the 
                 date class.  All methods are documented separately.
***********************************************************************/

// INCLUDE FILES
#include <iostream.h>      // cout, cin, cerr, etc...
#include <string.h>        // strcmp()
#include "logic.h"         // boolean typedefs
#include "date.h"          // date class declaration

// CONSTRUCTORS
//    each constructors simply assigns the integers used in construction
//    to the month, day and year fields of the object.  The constructors 
//    also perform bounds checking for the months and days
date::date (int x, int y, int z)
{
   if ((x < 1) || (x > 12)) {
      cout << "Illegal month.\n";
      month = 1; }
   else 
      month = x;

   switch (month) {
      case 1 : 
      case 3 : 
      case 5 : 
      case 7 : 
      case 9 : 
      case 10 : 
      case 12 : if ((y < 1) || (y > 31)) {
                   cout << "Illegal day.\n";
                   day = 1; }
                else 
                   day = y;
                break;
      case 2 : if ((y < 1) || (y > 28)) {
                  cout << "Illegal day.\n";
                  day = 1; }
               else
                  day = y;
               break;
      case 4 : 
      case 6 : 
      case 8 : 
      case 11 : if ((y < 1) || (y > 30)) {
                   cout << "Illegal day.\n";
                   day = 1; }
                else
                   day = y;
                break; 
      default : cout << "Bad month.\n";}
   year = z;

};    // end of date (int, int, int)

date::date (const date& given_date)
{
   month = given_date.month;
   day = given_date. day;
   year = given_date.year;
};    // end of date (date&)

/*
   DateToDay()
   
   ARGS : none
   RETURN : integer number of days represented by the month and day field
            of date object
   SIDE_EFFECTS : none
*/
int date::DateToDay (void)
{
   int result;
  
   switch (month) {
      case 1 : result = day;
               break;
      case 2 : result = 31 + day;
               break;
      case 3 : result = 59 + day;
               break;
      case 4 : result = 90 + day;
               break;
      case 5 : result = 120 + day;
               break;
      case 6 : result = 151 + day;
               break;
      case 7 : result = 181 + day;
               break;   
      case 8 : result = 212 + day;
               break;
      case 9 : result = 242 + day;
               break;
      case 10 : result = 273 + day;
                break;
      case 11 : result = 304 + day;
                break;
      case 12 : result = 334 + day;
                break; 
      default : cout << "Bad month.\n";}

   return result;
};  // end of DateToDay

/*
   DayToDate()
   
   ARGS : num_days = date in current year in terms of days
          current_year = current_year 
   RETURN : date object constructed by translating the num_days arg into
            month, day and year
   SIDE_EFFECTS : none
*/
date date::DayToDate (int num_days, int current_year)
{
   int temp_month;

   if (num_days > 365) {
      ++current_year;
      num_days -= 365; }

   if (num_days > 334)
      return date (12, num_days - 334, current_year);
   else if (num_days > 304)
     return date (11, num_days -304, current_year);
   else if (num_days > 273)
     return date (10, num_days - 273, current_year);
   else if (num_days > 242)
     return date (9, num_days - 242, current_year);
   else if (num_days > 212)
     return date (8, num_days - 212, current_year);
   else if (num_days > 181)
     return date (7, num_days - 181, current_year);
   else if (num_days > 151)
     return date (6, num_days - 151, current_year);
   else if (num_days > 120)
     return date (5, num_days - 120, current_year);
   else if (num_days > 90)
     return date (4, num_days - 90, current_year);
   else if (num_days > 59)
     return date (3, num_days - 59, current_year);
  else if (num_days > 31)
     return date (2, num_days - 31, current_year);
   else
     return date (1, num_days, current_year);
};  // end of DayToDate

/*
   operator+ ()
   
   ARGS : add_days = number of days to add to 'this' date
   RETURN : date object that is the sum of this and num_days
   SIDE_EFFECTS : none
*/
date date::operator+ (int add_days)
{
   date temp;   
   int num_days;

   num_days = DateToDay ();
   num_days += add_days;
   temp = DayToDate (num_days, year);

   return temp;
};  // end of oprator+

/*
   operator- ()
   
   ARGS : sub_days = number of days to subtract from 'this' date
   RETURN : date object that is the difference of this and num_days
   SIDE_EFFECTS : none
*/
date date::operator- (int sub_days)
{
   date temp;   
   int num_days;

   num_days = DateToDay ();
   num_days -= sub_days;
   if (num_days < 0)
      num_days = -num_days;
   temp = DayToDate (num_days, year);

   return temp;
}; // end of operator- (int)
   
/*
   operator> ()
   
   ARGS : cmp_date = date to compare 'this' to
   RETURN : integer that is 1 is the integer comparison is true and 0
            otherwise
   SIDE_EFFECTS : none
   NOTE : The comparison is simply done by first comparing years.  Then
          comparing months and finally days.
*/
int date::operator> (const date& cmp_date)
{
   int result;

   if (year > cmp_date.year)
      result = TRUE;
   else if (year <= cmp_date.year)
      result = FALSE;
   else if (month > cmp_date.month)
      result = TRUE;
   else if (month <= cmp_date.month)
      result = FALSE;
   else if (day > cmp_date.day)
     result = TRUE;
   else 
     result = FALSE;

   return result;
};  // end of operator>

/*
   operator< ()
   
   ARGS : cmp_date = date to compare 'this' to
   RETURN : integer that is 1 is the integer comparison is true and 0
            otherwise
   SIDE_EFFECTS : none
   NOTE : The comparison is simply done by first comparing years.  Then
          comparing months and finally days.
*/
int date::operator< (const date& cmp_date)
{
   int result;

   if (year > cmp_date.year)
      result = FALSE;
   else if (year < cmp_date.year)
      result = TRUE;
   else if (month >= cmp_date.month)
      result = FALSE;
   else if (month < cmp_date.month)
      result = TRUE;
   else if (day >= cmp_date.day)
      result = FALSE;
   else 
      result = TRUE;

   return result;
};  // end of operator<

/*
   operator== ()
   
   ARGS : cmp_date = date to compare 'this' to
   RETURN : integer that is 1 is the integer comparison is true and 0
            otherwise
   SIDE_EFFECTS : none
   NOTE : The comparison is simply done by first comparing years.  Then
          comparing months and finally days.
*/
int date::operator== (const date& cmp_date)
{
   if ((year == cmp_date.year) AND
       (month == cmp_date.month) AND
       (day == cmp_date.day))
       return TRUE;
   else
      return FALSE;
};  // end of operator==

/* 
   ChangDate ()
   
   ARGS : x = new month
          y = new day
          z = new year
   RETURN : new date object with the values of x, y and z assigned to month,
            day and year respectively
   SIDE_EFFECTS : none
*/
date& date::ChangeDate (int x, int y, int z)
{
   return *(new date(x, y, z));
};  // end of ChangeDate;

/*
   operator<< ()
   
   ARGS : S = ostream to to
          print_date = date to be printed
   RETURN : reference to ostream that was put to
   SIDE_EFFECTS : print_date is put to stream S
*/
ostream& operator<< (ostream& S, const date& print_date)
{
   char* month_string;

   switch (print_date.month) {
      case 1 : month_string = strdup ("January");
	       break;
      case 2 : month_string = strdup ("Febuary");
	       break;
      case 3 : month_string = strdup ("March");
	       break;
      case 4 : month_string = strdup ("April");
	       break;
      case 5 : month_string = strdup ("May");
	       break;
      case 6 : month_string = strdup ("June");
	       break;
      case 7 : month_string = strdup ("July");
	       break;
      case 8 : month_string = strdup ("August");
	       break;
      case 9 : month_string = strdup ("September");
	       break;
      case 10 : month_string = strdup ("October");
		break;
      case 11 : month_string = strdup ("November");
		break;
      case 12 : month_string = strdup ("December");
		break; }


   return (S<<month_string<< " "<<print_date.day<<", "<<print_date.year);
};   // end of operator<<