Hash table that uses the link address method to resolve conflicts

/*
Author: Xu **
Date: 12.29 918
Version: V1.0
Role: simple employee management system
Each employee's information includes: number, name, gender, date of birth,
Education, job title, phone number, address, etc. The system functions include:
1. Query: Search for employees based on specific conditions
2. Modify: Modify the information of an employee by number.
3. insert: new employee information
4. Delete: delete employee information by number
5. Sorting: sort the information of all employees according to specific conditions.
*/
# Include <iostream>
Using namespace STD;
# Include <stdio. h>
# Include <string. h>

# Define hashkey 13
# Define nullkey-1
# Define max 20

Typedef struct employee
{
Int key_code;
Char name [30];
Char sex;
Char borndate [30];
Char education [10];
Char position [15];
Char phone [15];
Char ADDR [30];
Struct employee * next;
} Employee;

Typedef struct hashtable // use the link address method to solve the conflict
{
Int key;
Struct employee * next;
} Hashtable [Max];

/// // Function /////////////////
Int Hash (INT key) // Hash Function
{
Int mode = Key % hashkey;
Return mode;
}
Void hash_init (hashtable HT) // hash table Initialization
{
Int I;
For (I = 0; I <Max; I ++)
{
HT [I]. Key = nullkey;
HT [I]. Next = NULL;
}
}
Int hash_insert (hashtable HT, employee * em)
{
Int key = hash (EM-> key_code );
Employee * P;
If (HT [Key]. Key = nullkey)
{
HT [Key]. Key = key;
HT [Key]. Next = em;
}
Else if (HT [Key]. Key = Key) // if a conflict occurs, use the link address to resolve the conflict.
{
P = HT [Key]. Next;
While (p-> next! = NULL) // find the insert position and insert it to the end of the table Synonym
{
P = p-> next;
}
P-> next = em;
}
Return 1;
}
Employee * hash_search (hashtable HT, int key)
{
Int p0 = hash (key );
If (HT [P0]. Key = nullkey) return NULL;
Else if (HT [P0]. Key = P0) // if a group of the same words is found, search for them in the synonym
{
Employee * P = HT [P0]. Next;
While (P! = NULL)
{
If (p-> key_code = key)
{
Return P;
}
P = p-> next;
}
}
Return NULL;
}

Void modify (employee * em)
{
Int choice = 0;
Cout <"what to modify ====" <Endl;
Cout <"1. Position" <Endl;
Cout <"2. Phone" <Endl;
Cout <"3. ADDR" <Endl;
Cout <Endl <"option --";
Cin> choice;

Switch (choice)
{
Case 1:
Char position [10];
Memset (Position, 0x00, sizeof (position ));
Cout <"change :";
Cin> position;
Strcpy (EM-> position, position );
Cout <"OK! "<Endl;
Break;
Case 2:
Char phone [15];
Memset (phone, 0x00, sizeof (phone ));
Cout <"change :";
Cin> phone;
Strcpy (EM-> Phone, phone );
Cout <"OK! "<Endl;
Break;
Case 3:
Char ADDR [30];
Memset (ADDR, 0x00, sizeof (ADDR ));
Cout <"change :";
Cin> ADDR;
Strcpy (EM-> ADDR, ADDR );
Cout <"OK! "<Endl;
Break;
Default:
Cout <"you have selected an error. Please see the option number ~ "<Endl;
}
}
Int hash_modify (hashtable HT, int key)
{
Int p0 = hash (key );
If (HT [P0]. Key = nullkey) return nullkey;
Else if (HT [P0]. Key = P0)
{
Employee * P = HT [P0]. Next;
While (P! = NULL)
{
If (p-> key_code = key)
{
Modify (P );
Return P0;
}
P = p-> next;
}
}
Return nullkey;
}
Int hash_delete (hashtable HT, int key)
{
Int p0 = hash (key );
If (HT [P0]. Key = nullkey) return nullkey;
Else if (HT [P0]. Key = P0)
{
Employee * P = HT [P0]. Next, * pre = P;
While (P! = NULL)
{
If (p-> key_code = key)
{
If (P = HT [P0]. Next)
{
HT [P0]. Next = p-> next;
}
Else
{
Pre-> next = p-> next;
}
Free (P );
Return P0;
}
Pre = P;
P = p-> next;
}
}
Return nullkey;
}
Void swap (employee * Em1, employee * EM2)
{
Employee em_temp;
Em_temp.key_code = Em1-> key_code;
Em1-> key_code = EM2-> key_code;
EM2-> key_code = em_temp.key_code;
Strcpy (em_temp.addr, Em1-> ADDR );
Strcpy (Em1-> ADDR, EM2-> ADDR );
Strcpy (EM2-> ADDR, em_temp.addr );
Strcpy (em_temp.borndate, Em1-> borndate );
Strcpy (Em1-> borndate, EM2-> borndate );
Strcpy (EM2-> borndate, em_temp.borndate );
Strcpy (em_temp.education, Em1-> Education );
Strcpy (Em1-> Education, EM2-> Education );
Strcpy (EM2-> Education, em_temp.education );
Strcpy (em_temp.name, Em1-> name );
Strcpy (Em1-> name, EM2-> name );
Strcpy (EM2-> name, em_temp.name );
Strcpy (em_temp.phone, Em1-> phone );
Strcpy (Em1-> phone, EM2-> phone );
Strcpy (EM2-> phone, em_temp.phone );
Strcpy (em_temp.position, Em1-> position );
Strcpy (Em1-> position, EM2-> position );
Strcpy (EM2-> position, em_temp.position );
Em_temp.sex = Em1-> sex;
Em1-> sex = EM2-> sex;
EM2-> sex = em_temp.sex;
}
Int hash_sort (hashtable HT)
{
Int K;
For (k = 0; k <Max; k ++)
{
If (HT [K]. Key = nullkey)
Continue;
Else
{
Employee * P = HT [K]. Next, * q = p-> next;
While (P! = NULL)
{
While (Q! = NULL)
{
If (p-> key_code> q-> key_code)
{
Swap (p, q );
}
Q = Q-> next;
}
P = p-> next;
}
}
}
Return 1;
}
Employee * record_input ()
{
Employee * em = (employee *) malloc (sizeof (employee ));
Cout <"/T enter the employee ID :";
Cin> em-> key_code;
Cout <"/T enter the employee's name :";
Cin> em-> name;
Cout <"/T enter the gender (N or F ):";
Cin> em-> sex;
Cout <"/T enter the Date of Birth :";
Cin> em-> borndate;
Cout <"/T enter the education level :";
Cin> em-> education;
Cout <"/T enter the position :";
Cin> em-> position;
Cout <"/T enter the phone number :";
Cin> em-> phone;
Cout <"/T enter the residential address :";
Cin> em-> ADDR;
Em-> next = NULL;

Return em;
}

Int hash_create (hashtable HT)
{
Int COUNT = 1;
Employee * em;
Hash_init (HT );
// For (COUNT = 0; count <3; count ++) // create records for three employees first
Cout <"/T ================= create an employee information table ======================" <Endl;
While (count! = 0)
{
Em = record_input ();

If (hash_search (HT, Em-> key_code) = NULL)
Hash_insert (HT, EM );
Else
{
Count --;
Cout <"No. cannot be repeated ~ -_-"<Endl;
Cout <"is C re-input? 1 or 0, choose :";
Cin> count;
If (count! = 0)
Continue;
Else
Break;
}
Cout <"enter an employee again? 1 or 0, choose :";
Cin> count;
}

Printf ("/ncreate successfully! /N ");
Return 1;
}

Int menu ()
{
Int choice = 0;
Cout <"/T ========================= employee management system ================= ====== "<Endl;
Cout <"/T1, query: Search for employees by specific conditions (by number)" <Endl;
Cout <"/T2, modify: Modify an employee's information by number (by number)" <Endl;
Cout <"/T3, insert: new employee information" <Endl;
Cout <"/T4, delete: delete employee information by number" <Endl;
Cout <"/T5, sorting: sort the information of all employees according to specific conditions" <Endl;
Cout <"/T0, exit: exit the system" <Endl;
Cout <"/T ========================================= ===================" <Endl;
Cout <Endl <"/toption --";
Cin> choice;
Return choice;
}
//////////////////////////////////////// ////////
Int main ()
{
Int choice = 0, key = 0;
Employee * em;
Hashtable HT;
// Hash_init (HT );
Hash_create (HT );
Cout <"------------------ welcome to use this system ~ -------------------- "<Endl;
While (choice = menu ())
{
Switch (choice)
{
Case 1:
Cout <"/T enter employee ID :";
Cin> key;
Em = hash_search (HT, key );
If (em! = NULL)
{
Cout <"/T employee No.:" <em-> key_code <Endl ;;
Cout <"/T employee name:" <em-> name <Endl ;;
Cout <"/T gender (N or F):" <em-> sex <Endl;
Cout <"/T Date of Birth:" <em-> borndate <Endl;
Cout <"/T education level:" <em-> Education <Endl;
Cout <"/t position:" <em-> position <Endl;
Cout <"/T phone number:" <em-> phone <Endl;
Cout <"/T residential address:" <em-> ADDR <Endl;
}
Else
Cout <"/t does not have this employee ~ -_-"<Endl;
Break;
Case 2:
Cout <"/T enter the employee ID to be modified :";
Cin> key;
If (hash_search (HT, key )! = NULL)
If (-1! = Hash_modify (HT, key ))
Cout <"/T modified successfully! Performance_^ "<Endl;
Else
Cout <"/t does not have this employee ~ -_-"<Endl;
Break;
Case 3:
Em = record_input ();
If (hash_search (HT, Em-> key_code) = NULL)
If (hash_insert (HT, EM) cout <"/T inserted successfully! Performance_^ "<Endl;
Else
Cout <"/T already has this employee! Insertion failed! -_-"<Endl;
Break;
Case 4:
Cout <"/T enter the employee ID to delete :";
Cin> key;
If (-1! = Hash_delete (HT, key ))
Cout <"/T deleted successfully! Performance_^ "<Endl;
Else
Cout <"/T has not changed employee! -_-"<Endl;
Break;
Case 5:
Hash_sort (HT );
Cout <"/t finished sorting ~ Performance_^ "<Endl;
Break;
Default:
Cout <"/t you have selected an error. Please see the number of options ~ "<Endl;
}
}
Cout <"/T ---------- thanks for using this system! --------- "<Endl;
Cout <"/t" <Endl;
Return 0;
}