C Language implementation of hash table-Open addressing method

Header file:

#ifndef __hashtable_h#define __hashtable_h/********************* (square) Open addressing hashing ***************///if there is a conflict, try another unit, typedef unsigned int index;typedef index position;typedef int elementtype until empty cell is found; #define Mintablesize 5struct hashtable;typedef struct hashTable *hashtable;hashtable initializetable (int tablesize); void destorytable (HashTable H) ;p osition Find (ElementType key,hashtable h); void Insert (ElementType key,hashtable h); ElementType Retrieve (position p,hashtable h); hashTable ReHash (hashTable h); int Delete (ElementType key,hashtable h); int NextPrime (int tablesize); int isprime (int x); int Hash (ElementType key,int tablesize); enum Kindofentry{legitimate,empty , deleted};struct hashentry{elementtype element;enum kindofentry info;}; typedef struct HASHENTRY cell;struct hashtable{int Tablesize;cell *thecells;};

#endif

Implementation file:

#include "HashTable.h" #include <stdio.h> #include <stdlib.h>/*********************** development Method (square) ********* /hashtable initializetable (int tablesize) {hashTable table;int i;if (tablesize< Mintablesize) {printf ("Table size is too small\n"); exit (-1);} Table= (hashTable) malloc (sizeof (struct hashTable)), if (!table) {printf ("Out of space\n"), Exit (-1);} Table->tablesize=nextprime (tablesize); table->thecells= (cell*) malloc (sizeof (cell) *table->tablesize); (!table->thecells) {printf ("Out of space\n"); exit (-1);} for (i=0;i<table->tablesize;i++) Table->thecells[i].info=empty;return table;} void Destorytable (hashTable H) {free (h->thecells); H=null;} Position find (ElementType key,hashtable H) {position currentpos;int Collisionnum;collisionnum=0;currentpos=hash (key, H->tablesize); while (H->thecells[currentpos].info!=empty&&h->thecells[currentpos].element!=key ) {//Squared detection method Currentpos+=2*collisionnum-1;if (currentpos>=h->tablesize) currentpos-=h-> tablesize;} return currentpos;} int Delete (ElementType key,hashtable H) {position pos;pos=find (key,h); if (H->thecells[pos].info==empty) return 0; Else{h->thecells[pos].info=deleted;return 1;}} void Insert (ElementType key,hashtable H) {position pos;pos=find (key,h); if (h->thecells[pos].info!=legitimate) {h- >theCells[pos].info=legitimate; H->thecells[pos].element=key;}} ElementType Retrieve (position p,hashtable h) {}hashtable ReHash (hashTable h)//re-hash {int I,oldsize;cell *oldcells;o ldcells=h->thecells;oldsize=h->tablesize; H=initializetable (2*oldsize); for (i=0;i<oldsize;i++) {if (oldcells[i].info==legitimate) insert (Oldcells[i]. ELEMENT,H);} Free (oldcells); return H;} int nextprime (int tablesize) {while (1) {if (IsPrime (tablesize)) return tablesize;elsetablesize++;}} int isprime (int x) {int i;for (i=2;i*i<=x;i++) {if (x%i==0) return 0;} return 1;} int Hash (ElementType key,int tablesize) {return key%tablesize;} /**************************************************************************/

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C Language implementation of hash table-Open addressing method