How to count the number of collisions in hash table? - c

Question

Here's the task: "Develop a program for the formation and processing of hash tables, built on the principle of open addressing (private hashing). Practical evaluation of hash tables for the set structure, including the data key N-bit digital code (N >= 10). Explore two probing methods: linear and quadratic. Analyze and calculate the results obtained, first of all, the occurrence of collisons and the search time data for different indicators table coverage ratios"
???For some reason I can't do the last one. I can't count collisions and their output in any way, and calculate the search time. Suggest ideas for the algorithm, plz???
Here`s code:
#define _CRT_SECURE_NO_WARNINGS
#include<stdio.h>
#include<stdlib.h>
#include<string.h>
#define LEN 20
typedef struct inform {
char* key, * name;
} INFO;
typedef struct hash_table {
int count, size;
INFO** array;
}HTAB;
INFO* New_Item(char* key, char* name)
{
INFO* result = (INFO*)malloc(sizeof(INFO));
result->key = key;
result->name = name;
return result;
}
void free_item(INFO* item)
{
if (item != NULL)
free(item);
}
HTAB* NewHTAB(int size)
{
HTAB* result = (HTAB*)malloc(sizeof(HTAB));
result->count = 0;
result->size = size;
result->array = (INFO**)malloc(sizeof(INFO*) * size);
memset(result->array, NULL, sizeof(INFO*) * size);
return result;
}
void free_hash_table(HTAB* table)
{
if (table != NULL) {
for (int i = 0; i < table->size; i++) {
INFO* item = table->array[i];
if (item != NULL) free_item(item);
}
free(table->array);
free(table);
}
}
int ht_hasItem(HTAB* table, int idx)
{
return table->array[idx] != NULL;
}
int ht_IsFull(HTAB* table)
{
return table->count == table->size;
}
int Hash_Code(int key, int size)
{
return key % size;
}
int Insert(HTAB* table, char* keycpy, char* namecpy)
{
int result = 0;
char* key = _strdup(keycpy);
char* name = _strdup(namecpy);
if (ht_IsFull(table)) printf("Hash table is FULL!!!");
else {
INFO* item = New_Item(key, name);
int idx = Hash_Code(atoi(key), table->size);
//int h = 1;
while (ht_hasItem(table, idx)) {
idx = Hash_Code(idx + 1, table->size);
}
//idx = Hash_Code(idx + (h*h), table->size);
//h++;
table->array[idx] = item;
table->count++;
}
return result;
free(key);
free(name);
}
void Display(HTAB* table)
{
printf("-------------------------------------------------\n");
for (int i = 0; i < table->size; i++) {
if (ht_hasItem(table, i)) {
INFO* item = table->array[i];
printf(" %d\t| %s\t| %s \t|\n", i, item->key, item->name);
printf("-------------------------------------------------\n");
}
else {
printf(" %d\t| ---\t| \t---\t\t|\n", i);
printf("-------------------------------------------------\n");
};
}
printf("\n");
}
int Search(HTAB* table, char* key)
{
int result = -1;
int idx = Hash_Code(atoi(key), table->size);
// int h = 1;
while (ht_hasItem(table, idx)) {
if (strcmp(table->array[idx]->key, key) == 0) {
result = idx;
break;
}
else idx = Hash_Code(idx + 1, table->size);
//idx = Hash_Code(idx + (h*h), table->size);
//h++;
}
return result;
}
INFO* Remove(HTAB* table, char* key)
{
INFO* result = NULL;
int idx = Search(table, key);
if (idx != -1) {
result = table->array[idx];
table->array[idx] = NULL;
table->count--;
}
return result;
}
int main() {
int itemIdx = 0;
INFO* item = NULL;
HTAB* table = NewHTAB(30);
char name[LEN], key[LEN];
int choice = 0, c;
system("chcp 1251");
FILE* ftxt;
if (!(ftxt = fopen("RGR_2_AP.txt", "r"))) {
puts("\n File not found...\n");
return 0;
}
while (fscanf(ftxt, "%s%s", name, key) == 2)
Insert(table, key, name);
printf("\n Іndex\t| Кey\t| \t NAME\t\t|\n");
Display(table);
do {
printf("MENU-: \n1.Insert new item"
"\n2.Search item"
"\n3.Delet item"
"\n\n Please choose one point-:");
scanf_s("%d", &choice);
switch (choice) {
case 1:
printf("\nEnter name: ");
rewind(stdin);
gets_s(name);
printf("\nВведіть ключ: ");
gets_s(key);
while (strlen(key) < 10) {
printf("\nWrong key");
printf("\nTry again: ");
gets_s(key);
}
Insert(table, key, name);
printf("\n");
Display(table);
break;
case 2:
printf("\nEnter key: ");
rewind(stdin);
gets_s(key);
while (strlen(key) < 10) {
printf("\nWrong key");
printf("\nTry again: ");
gets_s(key);
}
itemIdx = Search(table, key);
if (itemIdx != -1) {
item = table->array[itemIdx];
printf("Item found: (%d, %s, %s)\n", itemIdx, item->key, item->name);
}
else printf("Item not found\n");
break;
case 3:
printf("\nEnter key: ");
rewind(stdin);
gets_s(key);
while (strlen(key) < 10) {
printf("\nWrong key");
printf("\nTry again: ");
gets_s(key);
}
Remove(table, key);
Display(table);
break;
default:
printf("Wrong Input\n");
}
printf("\n Do you want continue(enter 1 if yes)?-:\t");
scanf_s("%d", &c);
} while (c == 1);
free_hash_table(table);
printf("End...\n");
return 0;
}

Answer 1

You could add variables which count collisions in the Insert and Search methods, as well as the run time. You may need to return a list in that case, with the first element being the index, second being the # of collisions, and third being the run time.
Use the chrono library to time your functions.