Dentist-HashList.c

/*************************************************************************
        Copyright © 2021 Konstantinidis Konstantinos
	Licensed under the Apache License, Version 2.0 (the "License");
	you may not use this file except in compliance with the License.
	You may obtain a copy of the License at
        http://www.apache.org/licenses/LICENSE-2.0
	Unless required by applicable law or agreed to in writing, software
	distributed under the License is distributed on an "AS IS" BASIS,
	WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
	See the License for the specific language governing permissions and
	limitations under the License.
*************************************************************************/
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <ctype.h>

#define HMax 11
#define VMax 100
#define EndOfList -1

typedef enum{
    Whitening=1, Cleaning=2, Extraction=3
}service_type;

typedef struct{
	double paid;
	service_type service;
} visit_type;

typedef visit_type ListElementType;

typedef struct{
	int RecKey;
	ListElementType Data;
	int Link;
} ListElm;

typedef struct{
	int HashTable[HMax];
    int Size;
	int SubListPtr;
    int StackPtr;
	ListElm List[VMax];
} HashListType;

typedef enum{
    FALSE, TRUE
} boolean;

void CreateHashList(HashListType *HList);
int HashKey(int Key);
boolean FullHashList(HashListType HList);
void SearchSynonymList(HashListType HList,int KeyArg,int *Loc,int *Pred);
void SearchHashList(HashListType HList,int KeyArg,int *Loc,int *Pred);
void AddRec(HashListType *HList,ListElm InRec);
void menu(int *choice);
int GetCharacterSum(char *Name);
void NewVisit(HashListType *DB);
void SearchVisit(HashListType DB);

int main(){
    int choice;
    HashListType DB; //An imitation of a database
    CreateHashList(&DB);

    do{
        menu(&choice);

        if(choice == 1)
            NewVisit(&DB); //Make a new appointment
        else if(choice == 2)
            SearchVisit(DB); //Search for a client
    }while(choice != 3);

    printf("Exiting the program.. \n"); //If choice is 3 then terminate the program

    return 0;
}

/*This is the menu that will appear in the user screen 
The user will use one of the provided choices*/
void menu(int *choice){
    printf("\t\t\tMENU\n");
    printf("-------------------------------------------------\n");
    printf("1. INSERT APPOINTMENT\n");
    printf("2. PRINT CLIENT'S APPOINTMENTS\n");
    printf("3. EXIT\n");
    do{
        printf("\nEnter the number of your choice: ");
    	scanf("%d", choice);
    	if(*choice<1 || *choice>3){ //Get a choice between 1-3
            printf("This is not a given choice...\n\n");
    	}
    }while(*choice<1 && *choice>3);
}

//A method to get the HashKey
int HashKey(int Key){
	return Key%HMax;
}

//A method to create a Hash List
void CreateHashList(HashListType *HList){
	int index;

	HList->Size = 0;
	HList->StackPtr = 0;
    	index = 0;
	while(index<HMax){
		HList->HashTable[index] = EndOfList;
		index = index+1;
    	}

   	index = 0;
	while(index<VMax-1){
		HList->List[index].Link = index+1;
		HList->List[index].Data.paid = 0;
		HList->List[index].Data.service = 0;
		index += 1;
	}
	HList->List[index].Link = EndOfList;
}

//A method to see if the list is full
boolean FullHashList(HashListType HList){
	return(HList.Size==VMax);
}

//A method to search for synonyms in the hash list
void SearchSynonymList(HashListType HList,int KeyArg,int *Loc,int *Pred){
	int Next;

	Next = HList.SubListPtr;
	*Loc = -1;
	*Pred = -1;
	while(Next != EndOfList){
		if(HList.List[Next].RecKey == KeyArg){
			*Loc = Next;
			Next = EndOfList;
		}
		else{
			*Pred = Next;
			Next = HList.List[Next].Link;
		}
	}
}

//A method to search inside the hash list
void SearchHashList(HashListType HList,int KeyArg,int *Loc,int *Pred){
	int HVal;

	HVal = HashKey(KeyArg);
    	if(HList.HashTable[HVal] == EndOfList){
		*Pred = -1;
		*Loc = -1;
	}
	else{
		HList.SubListPtr = HList.HashTable[HVal];
		SearchSynonymList(HList,KeyArg,Loc,Pred);
	}
}

//A method to add a new record in the list
void AddRec(HashListType *HList,ListElm InRec){
	int Loc, Pred, New, HVal;

	if(!(FullHashList(*HList))){
		Loc = -1;
		Pred = -1;
		SearchHashList(*HList,InRec.RecKey,&Loc,&Pred);
		if(Loc == -1){
			HList->Size = HList->Size + 1;
			New = HList->StackPtr;
			HList->StackPtr = HList->List[New].Link;
			HList->List[New] = InRec;
			if(Pred==-1){
			    HVal = HashKey(InRec.RecKey);
                HList->HashTable[HVal] = New;
				HList->List[New].Link = EndOfList;
			}
			else{
                HList->List[New].Link = HList->List[Pred].Link;
				HList->List[Pred].Link = New;
			}
		}
		else
			printf("A client with the same name is already in the catalogue\n");
	}
	else
		printf("The list is full can't add more...");
}

/*A method to get the summary of the characters from the client's name
because we want to "save" the name as an integer and not a string*/
int GetCharacterSum(char *Name){
    int index;
    int key;
    char a = 'A' - 1;

    index = 0;
    key = 0;
    while(TRUE){
        if(index > strlen(Name))
            break;
        else
            key += (index + 1) * (Name[index] - a);

        index++;
    }
    return key;
}

//A method to create a new appointment
void NewVisit(HashListType *DB){
    char ch;
    ListElm AnItem;
    ListElementType visit;
    char client[20];

    do{
        printf("Enter the client's Name: ");
        scanf("%s", client);
        getchar();

        printf("Enter the service number:\n1) Whitening\n2) Cleaning\n3) Extraction\n");
        scanf("%d",&visit.service);
        while(visit.service<1 || visit.service>3){
            printf("Incorrect service.\n");
            printf("Please enter a correct service number:\n1) Whitening\n2) Cleaning\n3) Extraction\n");
            scanf("%d",&visit.service);
        }
        getchar();

        printf("Enter the amount paid: ");
        scanf(" %lf",&visit.paid);
        getchar();
        printf("\n");

        AnItem.Data = visit;
        AnItem.RecKey = GetCharacterSum(client);
        AddRec(DB, AnItem);

        printf("Continue Y/N: ");
        scanf(" %c", &ch);
        while(ch!= 'Y' && ch!= 'N'){
            printf("Wrong input.\n");
            printf("Continue Y/N: ");
            scanf(" %c", &ch);
        }
    }while(ch != 'N');
}

//A method to search for a client
void SearchVisit(HashListType DB){
    int Akey;
    int Loc, Pred;
    char client[20];
    int service;
    double paid;

    printf("Enter the client's Name: ");
    scanf(" %s", client);
    getchar();

    Akey = GetCharacterSum(client);
    SearchHashList(DB, Akey, &Loc, &Pred);

    if(Loc!=-1){
        printf("Service: %d\n", DB.List[Loc].Data.service);
        printf("Amount Paid: %.2f\n", DB.List[Loc].Data.paid);
    }
    else
        printf("This customer does not exist..\n\n\n");
}