#include <stdio.h>
#include <stdlib.h>

// c version of linked list, featuring malloc. See also node.cc for elegant C++ node definition
typedef struct node_s 		// real C
{  char * name;
    int   value;    		//price of fruit
   struct node_s *next;		// we'd like node*, but not defined yet
} node; 			// now we can declare or create nodes:


node* build(const char* filename)  // build linked list from a file
// return pointer to first node
{				// each line of form "apple  66"
   node* head=0;	// initially empty list
   node* tail;		// hold pointer to last node in list
   node* anode;
   char * afruit;
   int    aprice;
   FILE * f = fopen(filename,"r");
   
    // NOTE syntax for EOF test
   
   while(EOF != fscanf(f,"%ms%d", &afruit, &aprice)) { // implicit malloc for string
      // printf ("%s\n", afruit);
      anode = malloc(sizeof(node));		// allocate space for node
      anode -> name =  afruit;		// fill it in, point to str.
      anode -> value = aprice;
      anode -> next = 0;		// currently no next
      if (! head) 
	 head=tail=anode;		// it is first and last elem.
      else {
	tail -> next = anode;		// linked at tail
	tail = anode;			// it is new tail
      }
     
   }
   fclose(f);
   return head;			// list all set up
}

void list(node* head)
{   while (head)
  {	printf ("  %-12s  %4d\n", head->name, head->value); // -12 for left-justify
	head = head -> next;
  }
}

node* delete(char* victim, node* head) {
  //   delete (one) node matching victim, return possibly new head
  node* curr = head;
  node* prev;
  node* newhead;
  while (curr) {
   if ( strcmp (curr -> name, victim) == 0)   // found the victim
     if (curr==head)   {	// should deallocate 
        newhead = head -> next;	//first, save pointer to new head
        free( curr -> name); 		// release string space
	free (curr);			// release node space
        return newhead;
     }
     else
     {	prev -> next = curr -> next;	// link around curr
        free( curr -> name); 		// release string space
	free (curr);			// release node space
	return head;		// unchanged
     }
   prev = curr;		  // may need to link around a deletion 
   curr = curr -> next;   // keep looking
   }
   return head;			// unchanged
}
   
int main(){
   node* head = build("linklist.txt");
   list(head);	//see the list
   head = delete ("grape", head);
   puts("After delete----");
   list(head);	//see the list



return 0;
}