HOW TO FIND

[hari8929]

SUPPOSE I gave my input as 16 5 2013

how can i get output as tomorrow is not hoilday.

[Lachlan Easton]

std::cout << "tomorrow is not holiday\n";

[ErrorFree]

Logically you have to store these data (calendar with holidays) somewhere in the program. Multidimitional array can be use or use database.

[jumper007]

Firstly, the question is not clear.

If you wish to know which date is a holiday and which is not, as @ErrorFree mentioned, you are supposed to create a database with all those dates. Given you have the calendar stored in a file (suppose a .txt or maybe .dat one) you can call it in your program like this:

- Create a file stream for input.
- Read all the dates which are holidays.
- Store those dates in either an array or in a STL vector.

Example:

#include <iostream>
#include <fstream>  // required in order to use the file streaming

using namespace std;

/* Class definition and other stuff goes here */

const short MAX = 100; // Max number of days for the holiday array below

struct Date{ // Structure for date
     short DD;
     short MM;
     short YYYY;
} date, holiday[MAX]; // Declare a variable date of type Date and an array for the holidays

int main(void) {
   
     // Some code
     
     short i = 0;     

     fstream in("holidays.dat", ios::in); // Could be .txt or anything else
     
     while (in && !in.eof() && in.good()){  // Check the state of the file -- not end of file
          i++;
          in >> holiday[i].DD >> holiday[i].MM >> holiday[i].YYYY;
     }

     // Rest of the code


     // In order to check whether a date is a holiday or not:
     
     cin >> date.DD >> date.MM >> date.YYYY; // Read a date
   
     for (short j = 1; j <= i; ++j){
          if (date.DD == holiday[j].DD && date.MM == holiday[j].MM && date.YYYY == holiday[j].YYYY){
               cout << "The date " << date.DD << "/" << date.MM << "/" << date.YYYY << " is a holiday." << endl;
         }
     }

    // Maybe some other code
   
}

EDIT:

Example for the file "holidays.dat" (you can open that extension with notepad)

5 12 2013
6 12 2013
25 12 2013
26 12 2013
1 1 2014

I hope I made it clear.


NOTE: This is just an exemplification. You need to implement all this in your class!

[ne555]

> in >> holiday[++i].DD >> holiday[i].MM >> holiday[i].YYYY;
Undefined behaviour

> while (in && !in.eof() && in.good()){ // Check the state of the file -- not end of file
check the reading operation
while(in >> holiday[i].DD >> holiday[i].MM >> holiday[i].YYYY) ++i;

> fstream in("holidays.dat", ios::in);
Don't ask for what you won't use
std::ifstream in("holidays.dat");

> struct Date{/**/} date;
limit the scope of your variables (¿why global?)

> for (short j = 1; j <= i; ++j)
¿why are you throwing away holiday[0]?

[jumper007]

>

Undefined behaviour

Undefined what ?
It's a basic struct operation. Learnt that about 2 years ago among the first lessons.
Works PERFECTLY. (EDIT: Haven't seen that possible unexpected behaviour warning in my complier, my apologies).

>

check the reading operation

Yes. So, what's the problem with it ? It's a regular reading check of the file state.

>

Don't ask for what you won't use

I have also learnt using this from Doina Logofatu in order to declare a file stream.

>

limit the scope of your variables (¿why global?)

Just because it was an example. I said it is not the actual program. He has to implement that struct in a class.
He won't use any declaration like that at all. He will declare the DD, MM, YYYY as either private variables with accessor and mutator functions, or just as public variables.

>

why are you throwing away holiday[0]?

Because it's more handy and less confusing for a beginner to work with values starting from 1. And not 0. That's how I learnt programming.

Nowadays, I do use the element at position 0, but only if it represents a crucial problem in means of memory allocation and space restrictions.
If I were at the IOI or ACM, yes, I would definitely use 0 too. For home projects, no need.

Kind regards,
Raul Butuc.

[Cubbi]

Works PERFECTLY.

Define 'works'. It's an error to increment and read a scalar in the same expression (more or less, see http://en.cppreference.com/w/cpp/language/eval_order for more details

It's a regular reading check of the file state. Learnt that from Doina Logofatu,

I didn't believe it so I found that book...

ifstream in("boxes.in");
ofstream out("boxes.out");
while(in && !in.eof() && in >> vCBoxes){

that is seriously repeated over and over (and it's not even the most bizarre code it has)

Try to find a different book if you want to learn C++. A good start is the list at http://stackoverflow.com/questions/388242/the-definitive-c-book-guide-and-list

[JLBorges]

> Undefined what ?
> Works PERFECTLY.

Tip: Compile with all warnings enabled.

With -std=c++11 -Wall -Wextra (GCC), you would get:

in >> holiday[++i].DD >> holiday[i].MM >> holiday[i].YYYY; 
// *** warning: operation on 'i' may be undefined [-Wsequence-point] 

Even after removing the undefined behaviour, (and starting with position 1 instead of 0), this construct leads to a subtle error:

while (in && !in.eof() && in.good()){  // Check the state of the file -- not end of file
          ++i ;
          in >> holiday[i].DD >> holiday[i].MM >> holiday[i].YYYY;
}

The value of i would be one more that what it ought to be when the attempted input fails.

[jumper007]

Hmm ? So, let me see if I got it right.. I am not allowed to increment while reading ? Well, that's something my ex teacher taught me at school a looong time ago.

When I've been taught that, my teacher mentioned that the ++i, being a pre-incrementation will be done first. So at the time the holiday[i] is read, i is already equal to 1.

However, about that thing with the fstream I know I read it in one of her books or articles. I'm sure.. I don't know exactly which, but I can assure you I did.

About the while thingy I always thought it meant:

in => checks if file exists
!in.eof() => checks if not end of file
in.good() => checks if file is corrupted/finished/damaged/etc.. :|

I don't know to what extent that might be considered good or bad programming practice, but however, I'm still learning, so if that really isn't good, I will try to find a new style. Though, I am going to check that list of books and maybe buy some.

Kind regards,
Raul

[jumper007]

@http://en.cppreference.com/w/cpp/language/eval_order
i = i++ + 1; // undefined behavior (but i = ++i + 1; is well-defined) ? So, i = ++i + 1 is well-defined ? And in >> holidays[++i] isn't ? Hmm, well, I have to do some research on that.

[JLBorges]

> ? And in >> holidays[++i] isn't ?

There is no problem with

in >> holidays[++i]  ;
in >> holiday[i].MM >> holiday[i].YYYY;

But there is a problem with:
in >> holiday[++i].DD >> holiday[i].MM >> holiday[i].YYYY;

[jumper007]

Ahh.. I got it.. I guess this is my mistake. My teacher talked only about single variables and not about reading more than 1. I interpreted the information wrongly, it seems..

Thanks for clearing this out for me. Won't happen again.

Kind regards,
Raul