A simple information management system for students using linked lists

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

typedef struct STUDENT
{
int id;
Char name[20];
int age;
char sex;
Char birthday[20];
Char address[20];
Char phone[15];
Char email[30];
struct student *next;
}student;

Student *head = NULL;
int length;
void Create ()
{
Student *p1,*p2;
length = 0;
P1 = (student *) malloc (sizeof (student));
P1->id =-1;
if (head = = NULL)
{
head = p1;
}
printf ("Please enter student's number, name, age, gender, date of birth, address, telephone, e-mail: \ n");
while (1)
{
P2 = (student *) malloc (sizeof (student));
scanf ("%d%s%d%c%s%s%s%s",&p2->id,p2->name,&p2->age,&p2->sex,&p2->birthday,& P2->address,p2->phone,p2->email);
if (P2->id = = 0)
{
printf ("Linked list creation complete!") \ n ");
Break
}
length + +;
P1->next = p2;
P2->next = NULL;
P1 = p1->next;
}
return;
}

void Loadstudentinfromfile ()
{
Student *p,*q;
int C;
File* F;
f = fopen ("Input.txt", "RB");
if (f = = NULL)
{
return;
}
Fseek (F,0,seek_set);
p = (student *) malloc (sizeof (student));
P->next = NULL;
head = p;
while (!feof (f))
{
c = fgetc (f);
if (c! =-1)
{
Fseek (f,-1,seek_cur);
}
Else
{
return;
}
Q = (student *) malloc (sizeof (student));
FSCANF (F, "%d", &q->id);
FSCANF (F, "%s", q->name);
FSCANF (F, "%d", &q->age);
FSCANF (F, "%c", &q->sex);
FSCANF (F, "%s", Q->birthday);
FSCANF (F, "%s", q->address);
FSCANF (F, "%s", Q->phone);
FSCANF (F, "%s", Q->email);
Q->next = NULL;
P->next = q;
p = p->next;
Length ++;//chain table Lengths
}
}

void Modifystudentinfo ()
{
Student *p = head->next;
int num;
printf ("Please enter the student number to be modified:");
scanf ("%d", &num);
while (P! = NULL)
{
if (p->id = = num)
{
printf ("Prior to modification, student number%d is as follows: \ n", num);
printf ("%d%s%d%c%s%s%s%s", p->id,p->name,p->age,p->sex,p->birthday,p->address,p->phone,p- >email);
printf ("Please enter the student's new phone:");
GetChar ();
Gets (P->phone);
printf ("Please enter the student's new address:");
Gets (p->address);
printf ("Modified, student ID%d is as follows: \ n", num);
printf ("%d%s%d%c%s%s%s%s", &p->id,p->name,&p->age,p->sex,p->birthday,p->address,p- >phone,p->email);
return;
}
p = p->next;
}
if (p = = NULL)
{
printf ("The school number does not exist!") \ n ");
return;
}
}
void display ()
{
Student *p = head->next;
printf ("All student information in the linked list is as follows: \ n");
while (P! = NULL)
{
printf ("%d%s%d%c%s%s%s%s", p->id,p->name,p->age,p->sex,p->birthday,p->address,p->phone,p- >email);
printf ("\ n");
p = p->next;
}
return;
}

Void Search ()
{
int num,x;
Char name[20];
Student *p = head->next;
printf ("Please select Query method: \ n");
printf ("1, Inquiry \t2 by number, search by name \ n");
scanf ("%d", &x);
if (x = = 1)
{
printf ("Student number to find is:");
scanf ("%d", num);
while (P! = NULL)
{
if (p->id = = num)
{
printf ("Student information%d" is as follows: \ n ", num);
printf ("%d%s%d%c%s%s%s%s", p->id,p->name,p->age,p->sex,p->birthday,p->address,p->phone,p- >email);
return;
}
P = p->next;
}
if (p = = NULL)
{
printf ("No This record! \ n ");
}
}
Else if (x = = 2)
{
printf ("The student name to look for is:");
GetChar ();
gets (name);
P = head->next;
while (P! = NULL)
{
if (strcmp (p->name,name) = = 0)
{
printf ("Student name%s student information is as follows: \ n", name);
printf ("%d%s%d%c%s%s%s%s", p->id,p->name,p->age,p->sex,p->birthday,p->address,p->phone,p- >email);
return;
}
P = p->next;
}
if (p = = NULL)
{
printf ("No This record! \ n ");
}
}
return;
}

void Insert ()
{
int num,i;
Student *p,*q;
p = head;

printf ("Please enter the location you want to insert:");
scanf ("%d", &num);
if (num > Length)
{
printf ("Cannot find the inserted location \ n");
return;
}
Else
{
printf ("Please enter the information for the student you want to insert: \ n");
Q = (student *) malloc (sizeof (student));
scanf ("%d%s%d%c%s%s%s%s", &q->id,q->name,&q->age,&q->sex,q->birthday,q->address, Q->phone,q->email);
while (P! = NULL)
{
if (P->id = = Q->id)
{
printf ("The school number already exists and cannot be inserted!") \ n ");
return;
}
p = p->next;
}
p = head;
for (i=0; i<num; ++i)
{
p = p->next;
}
Q->next = p->next;
P->next = q;
length + +;
printf ("Insert succeeded! \ n ");
return;
}
}

void Delete ()
{
int num;
Student *p,*q;
Q = head;
p = head->next;
printf ("Please enter the student number for deletion: \ n");
scanf ("%d", &num);

while (P! = NULL)
{
if (p->id = = num)
{
Q->next = p->next;
Free (p);
Length--;
printf ("Delete succeeded! \ n ");
return;
}
p = p->next;
Q = q->next;
}
if (p = = NULL)
{
printf ("Could not find the number to delete!") \ n ");
return;
}
}

void menu ()
{
printf ("___________________________________________________\n");
printf ("| Student information Management System |\n");
printf ("|, exit System |\n");
printf ("|\n", enter student information);
printf ("|\n, establish linked list");
printf ("|3, display linked list |\n");
printf ("|4, find an element in the list |\n");
printf ("|5, deleting the node of the specified study number in the list |\n");
printf ("|6, insert a new node in the specified position |\n");
printf ("|7, revise student information |\n");
printf ("__________________________________________________\n");
return;
}

int main (void)
{
int A;
menu ();
while (1)
{
printf ("Please enter the appropriate function:");
scanf ("%d", &a);
Switch (a)
{
Case 0:
return 0;
Case 1:
Loadstudentinfromfile ();
menu ();
break;
Case 2:
Create ();
menu ();
break;
Case 3:
if (head)
{
display ();
menu ();
}
Else
{
printf ("The list is empty, please build the list first!") \ n ");
Menu ();
}
Break;
Case 4:
if (head)
{
Search ();
menu ();
}
Else
{
printf ("The list is empty, please build the list first!") \ n ");
Menu ();
}
Break;
Case 5:
if (head)
{
Delete ();
menu ();
}
Else
{
printf ("The list is empty, please build the list first!") \ n ");
Menu ();
}
Break;
Case 6:
if (head)
{
Insert ();
menu ();
}
Else
{
printf ("The list is empty, please build the list first!") \ n ");
Menu ();
}
Break;
Case 7:
if (head)
{
Modifystudentinfo ();
menu ();
}
Else
{
printf ("The list is empty, please build the list first!") \ n ");
Menu ();
}
Break;
Default:
break;
}
}
System ("pause");
return 0;
}

Using linked lists to implement a simple student information management system