https://medium.com/jungletronics/university-catalog-v1-9db8cfc526a2

12_universitycatalog_v1.c

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

#define VECTORSIZE 10

//Typedef definition
typedef struct HashList
{	int id;
    	char student[50];
    	char email[50];
	struct HashList *prox;
} HashList_t;

typedef struct Table
{
	int Size;
	HashList_t **ListKey;
} Table_t;

//Prototypes
int menu();
int HashingFunction(int);
void InsertHash(Table_t *, int, char[], char[], int);
void ShowHash(Table_t *);
void RemoveHash(Table_t *, int, int);
void SearchHash(Table_t *, int, int);

int main()
{
	int op, c, id, pos;
	Table_t *TableHash = (Table_t *)malloc(sizeof(Table_t));
	TableHash->Size = VECTORSIZE;
	TableHash->ListKey = (HashList_t **)malloc(VECTORSIZE * sizeof(HashList_t *));
    	char student[50], email[50];

	for (int i = 0; i < VECTORSIZE; i++)
		TableHash->ListKey[i] = NULL;

	while (1)
	{
		op = menu();
		switch (op)
		{
		case 1: //insert
			printf("Type the id of the student: ");
			scanf_s("%d", &id);
			while ((c = getchar()) != '\n' && c != EOF)
			{
			}
            printf("Type the name of the student: ");
			scanf_s("%[a-zA-z ]]", &student);
			while ((c = getchar()) != '\n' && c != EOF)
			{
			}
            printf("Type the email of the student: ");
			scanf_s("%[a-zA-z@ ]]", &email);
			while ((c = getchar()) != '\n' && c != EOF)
			{
			}
			pos = HashingFunction(id);
			printf("Inserting in position %d of Table...\n", pos);
			system("pause");
			InsertHash(TableHash, id, student, email, pos);
			break;
		case 2: //remove
			printf("Type the number to remove: ");
			scanf_s("%d", &id);
			while ((c = getchar()) != '\n' && c != EOF)
			{
			}
			pos = HashingFunction(id);
			printf("Removing from position %d of Table...\n", pos);
			printf("WARNING: The System returns if nothing is found, ok? \n");
			system("pause");
			RemoveHash(TableHash, id, pos);
			break;
		case 3: //search
			printf("Type the number to search: ");
			scanf_s("%d", &id);
			while ((c = getchar()) != '\n' && c != EOF)
			{
			}
			pos = HashingFunction(id);
			printf("Searching for idber %i ...\n", id);
			printf("WARNING: The System returns if nothing is found, ok? \n");
			system("pause");
			SearchHash(TableHash, id, pos);
			system("pause");
			break;
		case 4: //show
			ShowHash(TableHash);
			system("pause");
			break;
		case 5:
			return 0;
			break;
		default:
			printf("Invalid\n");
			break;
		}
	}
	return 0;
}

int menu()
{
	int op, c;
	system("Cls");

	printf("1. Insert in Hash\n");
	printf("2. Remove from Hash\n");
	printf("3. Search the Hash\n");
	printf("4. Show the Hash\n");
	printf("5. Exit\n");
	printf("Choose the operation: ");

	scanf_s("%d", &op);
	while ((c = getchar()) != '\n' && c != EOF)
	{
	}

	system("Cls");
	return op;
}

int HashingFunction(int id)
{
	return (id % VECTORSIZE);
}

void InsertHash(Table_t *TableHash, int id, char student[50], char email[50], int pos)
{
	HashList_t *NewItem;
	NewItem = (HashList_t *)malloc(sizeof(HashList_t));
	NewItem->id = id;
    	strcpy(NewItem->student, student);
    	strcpy(NewItem->email, email);
	NewItem->prox = NULL;

	NewItem->prox = TableHash->ListKey[pos];
	TableHash->ListKey[pos] = NewItem;
}

void SearchHash(Table_t *TableHash, int id, int pos)
{
	HashList_t *ScanItem;
	ScanItem = (HashList_t *)malloc(sizeof(TableHash));
	ScanItem = TableHash->ListKey[pos];

	HashList_t *Auxiliar;
	Auxiliar = (HashList_t *)malloc(sizeof(HashList_t));

	if (TableHash->ListKey[pos]->id == id)
	{
		TableHash->ListKey[pos] = TableHash->ListKey[pos]->prox;
		printf("YES, The The student RU-%d was found in table!\n", id);
	}
	else
	{
		while (ScanItem->id != id)
		{
			Auxiliar = ScanItem;
			ScanItem = ScanItem->prox;
		}
		Auxiliar->prox = ScanItem->prox;
		printf("YES, The student RU-%d was found in table!\n", id);
	}
}

void RemoveHash(Table_t *TableHash, int id, int pos)
{
	HashList_t *ScanItem;
	ScanItem = (HashList_t *)malloc(sizeof(TableHash));
	ScanItem = TableHash->ListKey[pos];

	HashList_t *Auxiliar;
	Auxiliar = (HashList_t *)malloc(sizeof(HashList_t));

	if (TableHash->ListKey[pos]->id == id)
	{
		TableHash->ListKey[pos] = TableHash->ListKey[pos]->prox;
		free(ScanItem);
	}
	else
	{
		while (ScanItem->id != id)
		{
			Auxiliar = ScanItem;
			ScanItem = ScanItem->prox;
		}
		Auxiliar->prox = ScanItem->prox;
		free(ScanItem);
	}
}

void ShowHash(Table_t *TableHash)
{
	int v;
	for (v = 0; v < TableHash->Size; v++)
	{
		HashList_t *ScanItem = TableHash->ListKey[v];
		printf("\n List of keys by position %d:\n ", v);
		while (ScanItem != NULL)
		{
			printf("%d -> ", ScanItem->id);
        		printf("\n_____________________________________\n");
        		printf("RU: %i\n", ScanItem->id);
       		 	printf("Student: %s\n", ScanItem->student);
        		printf("Email: %s\n", ScanItem->email);
        		printf("_____________________________________\n");
			ScanItem = ScanItem->prox;
		}
		printf("\n");
	}
}