//  Times.m  Copyright (c) Kari Laitinen

//  http://www.naturalprogramming.com

//  2013-07-16  Objective-C version of this file was created.
//  2013-07-16  Last modification.

//  Ohjelma toimii mutta ....
//  PitŠŠ selvittŠŠ miten tehdŠŠn virtuaalifunktioita OC:sssŠ.

#include  <stdio.h>
#import   <Foundation/Foundation.h>
#include  <time.h>

@interface CurrentTime : NSObject
{
   int  current_hours ;
   int  current_minutes ;
   int  current_seconds ;
}

- (id) init ;
- (void) print ;

@end

@implementation CurrentTime

- (id) init
{
   self = [ super init ] ;
   
   if ( self )
   {
      // Function time gives us seconds that have elapsed
      // since 1.1.1970 00:00:00. Function localtime converts
      // these seconds to more meaningful time units.

      time_t  seconds_since_1970  ; 

      time( &seconds_since_1970 ) ;

      current_hours    = localtime( &seconds_since_1970 ) -> tm_hour  ;
      current_minutes  = localtime( &seconds_since_1970 ) -> tm_min  ;
      current_seconds  = localtime( &seconds_since_1970 ) -> tm_sec  ;
   }
   
   return self ;
}

- (void) print
{
}

@end

//  It is not entirely true that the 12-hour a.m./p.m. time
//  would be used everywhere in America, and the 24-hour time
//  would be used everywhere in Europe. The names AmericanTime
//  and EuropeanTime just happen to be nice names to
//  distinguish these two different ways to display time.


@interface AmericanTime  :  CurrentTime

- (void) print ;

@end


@implementation AmericanTime

- (void) print
{
   int  american_hours[]  =

     { 12, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11,
       12, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11  } ;

   printf( "%d:%02d:%02d",  american_hours[ current_hours ],
           current_minutes, current_seconds ) ;

   if ( current_hours  <  12 )
   {
      printf( " a.m." ) ;
   }
   else
   {
      printf( " p.m." ) ;
   }
}

@end


@interface EuropeanTime  :  CurrentTime

- (void) print ;

@end


@implementation EuropeanTime

- (void) print
{
   printf( "%d:%02d:%02d",  current_hours,
           current_minutes, current_seconds ) ;
}

@end

int main( void )
{
   NSAutoreleasePool* autorelease_pool = [ [ NSAutoreleasePool alloc ] init ] ;

   CurrentTime*   time_to_show ;

   printf( "\n Type 12 to see the time in 12-hour a.m./p.m format."
           "\n Any other number gives the 24-hour format. " ) ;

   int  user_response ;
   scanf( "%d",  &user_response ) ;

   if ( user_response  ==  12 )
   {
      time_to_show  =  [ [ AmericanTime alloc ] init ] ;
   }
   else
   {
      time_to_show  =  [ [ EuropeanTime alloc ] init ] ;
   }

   printf( "\n  The time is now " ) ;

   [ time_to_show print ] ;

   printf( "\n\n" ) ;

   [ autorelease_pool drain ] ;
}