/*
 * hash.c
 * Creates a hash table using libc hash functions. User enters the name of a
 * state as a parameter and the corresponding state capital is returned from
 * a hash table lookup.
 *
 * NOTE: this example uses static global arrays as data for hash entries so we
 * dont need to worry about deallocating when destroying the hash table.
 * However, if you use dynamic memory for your hash entries you must maintain
 * an array of all entries created. The hdestroy function frees the memory used
 * by the hash table but does not deallocate the "data" pointer in the ENTRY
 * structure. e.g.:
 *
 * ENTRY my_entries[100];
 * ...
 * for(i=0; i<100; i++)
 * 	free_data(my_entries.data);
 * hdestroy();
 */

#include <stdio.h>
#include <errno.h>
#include <search.h>
#include <stdlib.h>
#include <memory.h>
#include <ctype.h>

#define NUM_STATES 50

ENTRY statecapitals[NUM_STATES];

char *states[] = {"alabama","alaska","arizona","arkansas","california","colorado","connecticut",
		"delaware","florida","georgia","hawaii","idaho","illinois","indiana","iowa",
		"kansas","kentucky","louisiana","maine","maryland","massachusetts","michigan",
		"minnesota","mississippi","missouri","montana","nebraska","nevada","new hampshire",
		"new jersey","new mexico","new york","north carolina","north dakota","ohio","oklahoma",
		"oregon","pennsylvania","rhode island","south carolina","south dakota","tennessee","texas",
		"utah","vermont","virginia","washington","west virginia","wisconsin","wyoming"};

char *capitals[]={"Montgomery","Juneau","Phoenix","Little Rock","Sacramento","Denver","Hartford",
		"Dover","Tallahassee","Atlanta","Honolulu","Boise","Springfield","Indianapolis",
		"Des Moines","Topeka","Frankfort","Baton Rouge","Augusta","Annapolis","Boston",
		"Lansing","St. Paul","Jackson","Jefferson City","Helena","Lincoln","Carson City",
		"Concord","Trenton","Santa Fe","Albany","Raleigh","Bismarck","Columbus","Oklahoma City",
		"Salem","Harrisburg Island","Providence","Columbia","Pierre","Nashville","Austin",
		"Salt Lake City","Montpelier","Richmond","Olympia","Charleston","Madison","Cheyenne"};


int main(int argc, char **argv)
{
	ENTRY search;
	ENTRY *ret;
	int i;
	char *statebuf;

	if(argc!=2)
	{
		fprintf(stdout,"usage: %s <state>\n",argv[0]);
		fflush(stdout);
		return -1;
	}

	hcreate(NUM_STATES);
	for(i=0; i<NUM_STATES; i++)
	{
		statecapitals[i].key=states[i];
		statecapitals[i].data=capitals[i];

		if(!(ret=hsearch(statecapitals[i],ENTER)))
		{
			fprintf(stdout,"hsearch failed while entering data\n");
			fflush(stdout);
			return -1;
		}
	}

	statebuf = (char*) malloc(sizeof(char)*strlen(argv[1])+1);
	statebuf[strlen(argv[1])]=0;

	for(i=0; i<strlen(argv[1]); i++)
	{
		statebuf[i]=tolower(argv[1][i]);
	}

	search.key = statebuf;

	if(!(ret=hsearch(search,FIND)))
	{
		fprintf(stdout,"hsearch failed for key %s\n",argv[1]);
		fflush(stdout);
	}
	else
	{
		fprintf(stdout,"%s\n",(char*)ret->data);
		fflush(stdout);
	}

	free(statebuf);
	hdestroy();

	return 0;
}