Lab 12: class list_t

Objectives:

Assignment

1. Following lab8, and object notes,
   • convert the list_t object in the list.h interface to a doubly-linked list, with link_t *head and link_t *tail nodes,
   • provide the following object member functions:

     // - instance methods
       // constructors (overloaded)
     - (id)       init;
     
       // accessor/mutator
     
       // operators
     - (litr_t *) push_back: (id) _data;
     - (litr_t *) insert: (litr_t *) _litr: (id) _data;
     - (void)     pop_front;
     - (litr_t *) erase: (litr_t *) _litr;
     
       // members
     - (id)       front;
     - (id)       back;
     - (litr_t *) begin;
     - (litr_t *) end;
     - (bool)     empty;
     		

   • You will also need a link_t object that contains id data;, link_t *prev;, and link_t *next; pointers along with corresponding accessor/mutator member functions
   • This implementation of the doubly-linked list also moves the link_t *current; pointer from the list_t structure—this pointer now is moved into its own object definition, litr_t, and as such, the litr_t object must now be provided with constructors, accessor/mutator functions as well as operators next and prev which advance or move back the current pointer and return itself.
   • The litr_t object should also have a bool member function called equiv which tests another litr_t object for equivalence (whether their current pointers point to the same thing).
2. Use the same data_t object definition as in an earlier lab.
3. Your code should be such that the following main() routine works unaltered:

   int main(int argc, const char *argv[])
   {
           NSAutoreleasePool *pool = [[NSAutoreleasePool alloc] init];
           NSString *str;
   
           int     num;
           char    nam[NAME_LEN];
           list_t *list = [(list_t *)[list_t alloc] init];
           litr_t *litr = nil;
           data_t *data = nil;
   
     NSLog(@"main start");
   
     while(scanf("%s %d",nam,&num) == 2) {
     //fprintf(stderr,"%s %d\n",nam,num);
     //str = [[NSString alloc] initWithCString: nam]; // deprecated, do not use
       str = [[NSString alloc] initWithUTF8String: nam];
       // cast sender to proper class type eliminates warning about amgiguous init
     //[list insert: [list end]: [(data_t *)[data_t alloc] init: str: num]];
       [list push_back: [(data_t *)[data_t alloc] init: str: num]];
     }
   
     NSLog(@"printing list");
     litr = [list begin];
     while(![litr equiv: [list end]]) {
       [[litr data] print: stderr];
       [litr next];
     }
   
     NSLog(@"printing list");
     for(litr = [list begin]; ![litr equiv: [list end]]; [litr next])
       [[litr data] print: stderr];
   
     NSLog(@"popping list");
     [[list front] print: stderr];
     [list pop_front];
   
     NSLog(@"printing list");
     for(litr = [list begin]; ![litr equiv: [list end]]; [litr next])
       [[litr data] print: stderr];
   
     NSLog(@"deleting list");
     while(![list empty]) [list pop_front];
   
     NSLog(@"printing list");
     for(litr = [list begin]; ![litr equiv: [list end]]; [litr next])
       [[litr data] print: stderr];
   
     NSLog(@"deleting list again");
     while(![list empty]) [list pop_front];
   
     NSLog(@"printing list again");
     for(litr = [list begin]; ![litr equiv: [list end]]; [litr next])
       [[litr data] print: stderr];
   
     [pool drain];
   
     return 0;
   }
   	

4. Sample input (entered by user):
   

   Mike    1234
   Bill    3212
   Sarah   1321 
   John    1021
   Carol   3223
   Debbie  4231
   Gary    9321
   Ann     1231
   Dale    7231
   Lynn    8133
   Patty   9999
   	

5. Sample output (note that the timestamps will differ):
   

   2013-01-22 14:33:57.347 main[87921:903] main start
   2013-01-22 14:33:57.364 main[87921:903] printing list
   Mike 1234
   Bill 3212
   Sarah 1321
   John 1021
   Carol 3223
   Debbie 4231
   Gary 9321
   Ann 1231
   Dale 7231
   Lynn 8133
   Patty 9999
   2013-01-22 14:33:57.364 main[87921:903] printing list
   Mike 1234
   Bill 3212
   Sarah 1321
   John 1021
   Carol 3223
   Debbie 4231
   Gary 9321
   Ann 1231
   Dale 7231
   Lynn 8133
   Patty 9999
   2013-01-22 14:33:57.364 main[87921:903] popping list
   Mike 1234
   2013-01-22 14:33:57.365 main[87921:903] printing list
   Bill 3212
   Sarah 1321
   John 1021
   Carol 3223
   Debbie 4231
   Gary 9321
   Ann 1231
   Dale 7231
   Lynn 8133
   Patty 9999
   2013-01-22 14:33:57.365 main[87921:903] deleting list
   2013-01-22 14:33:57.366 main[87921:903] printing list
   2013-01-22 14:33:57.366 main[87921:903] deleting list again
   2013-01-22 14:33:57.367 main[87921:903] printing list again
   	

Turn in

1. A README file containing
   1. Course id--section no
   2. Name
   3. Lab description
   4. Brief solution description (e.g., program design, description of algorithm, etc., however appropriate).
   5. Lessons learned, identified interesting features of your program
   6. Any special usage instructions
2. Makefile
3. source code (.h headers and .c source)
4. object code (do a make clean before tar)

How to hand in