Student record management system using linked list

Prerequisites: Linked list
Problem: Create a student Record Management system that can perform the following operations:

• Insert Student record
• Delete student record
• Show student record
• Search student record

The student record should contain the following items

• Name of Student
• Roll Number of Student
• Course in which Student is Enrolled
• Total Marks of Student

Approach: With the basic knowledge of operations on Linked Lists like insertion, deletion of elements in the Linked list, the student record management system can be created. Below are the functionalities explained that are to be implemented:

• Check Record: It is a utility function of creating a record it checks before insertion whether the Record Already Exists or not. It uses the concept of checking for a Node with given Data in a linked list.
• Create Record: It is as simple as creating a new node in the Empty Linked list or inserting a new node in a non-Empty linked list.
• Search Record: Search a Record is similar to searching for a key in the linked list. Here in the student record key is the roll number as the roll number is unique for every student.
• Delete Record: Delete Record is similar to deleting a key from a linked list. Here the key is the roll number. Delete record is an integer returning function it returns -1 if no such record with a given roll number is found otherwise it deletes the node with the given key and returns 0.
• Show Record: It shows the record is similar to printing all the elements of the Linked list.

Exception Handling

Although the implementation of exception handling is quite simple few things must be taken into consideration before designing such a system:

• Roll Number must be used as a key to distinguish between two different records so while inserting a record check whether this record already exists in our database or not if it already exists then immediately report to the user that the record already exists and insert that record in the database.
• The record should be inserted in sorted order for this to make the roll number a key and use the inserting node in the sorted linked list.

Below is the implementation of the above approach:

C++

// C++ program for the above approach
#include <bits/stdc++.h>
using namespace std;

// Node Class
class Node {
public:
    int roll;
    string Name;
    string Dept;
    int Marks;
    Node* next;
};

// Stores the head of the Linked List
Node* head = new Node();

// Check Function to check that if
// Record Already Exist or Not
bool check(int x)
{
    // Base Case
    if (head == NULL)
        return false;

    Node* t = new Node;
    t = head;

    // Traverse the Linked List
    while (t != NULL) {
        if (t->roll == x)
            return true;
        t = t->next;
    }

    return false;
}

// Function to insert the record
void Insert_Record(int roll, string Name,
                   string Dept, int Marks)
{
    // if Record Already Exist
    if (check(roll)) {
        cout << "Student with this "
             << "record Already Exists\n";
        return;
    }

    // Create new Node to Insert Record
    Node* t = new Node();
    t->roll = roll;
    t->Name = Name;
    t->Dept = Dept;
    t->Marks = Marks;
    t->next = NULL;

    // Insert at Begin
    if (head == NULL
        || (head->roll >= t->roll)) {
        t->next = head;
        head = t;
    }

    // Insert at middle or End
    else {
        Node* c = head;
        while (c->next != NULL
               && c->next->roll < t->roll) {
            c = c->next;
        }
        t->next = c->next;
        c->next = t;
    }

    cout << "Record Inserted "
         << "Successfully\n";
}

// Function to search record for any
// students Record with roll number
void Search_Record(int roll)
{
    // if head is NULL
    if (!head) {
        cout << "No such Record "
             << "Available\n";
        return;
    }

    // Otherwise
    else {
        Node* p = head;
        while (p) {
            if (p->roll == roll) {
                cout << "Roll Number\t"
                     << p->roll << endl;
                cout << "Name\t\t"
                     << p->Name << endl;
                cout << "Department\t"
                     << p->Dept << endl;
                cout << "Marks\t\t"
                     << p->Marks << endl;
                return;
            }
            p = p->next;
        }

        if (p == NULL)
            cout << "No such Record "
                 << "Available\n";
    }
}

// Function to delete record students
// record with given roll number
// if it exist
int Delete_Record(int roll)
{
    Node* t = head;
    Node* p = NULL;

    // Deletion at Begin
    if (t != NULL
        && t->roll == roll) {
        head = t->next;
        delete t;

        cout << "Record Deleted "
             << "Successfully\n";
        return 0;
    }

    // Deletion Other than Begin
    while (t != NULL && t->roll != roll) {
        p = t;
        t = t->next;
    }
    if (t == NULL) {
        cout << "Record does not Exist\n";
        return -1;
        p->next = t->next;

        delete t;
        cout << "Record Deleted "
             << "Successfully\n";

        return 0;
    }
}

// Function to display the Student's
// Record
void Show_Record()
{
    Node* p = head;
    if (p == NULL) {
        cout << "No Record "
             << "Available\n";
    }
    else {
        cout << "Index\tName\tCourse"
             << "\tMarks\n";

        // Until p is not NULL
        while (p != NULL) {
            cout << p->roll << "    \t"
                 << p->Name << "\t"
                 << p->Dept << "\t"
                 << p->Marks << endl;
            p = p->next;
        }
    }
}

// Driver code
int main()
{
    head = NULL;
    string Name, Course;
    int Roll, Marks;

    // Menu-driven program
    while (true) {
        cout << "\n\t\tWelcome to Student Record "
                "Management System\n\n\tPress\n\t1 to "
                "create a new Record\n\t2 to delete a "
                "student record\n\t3 to Search a Student "
                "Record\n\t4 to view all students "
                "record\n\t5 to Exit\n";
        cout << "\nEnter your Choice\n";
        int Choice;

        // Enter Choice
        cin >> Choice;
        if (Choice == 1) {
            cout << "Enter Name of Student\n";
            cin >> Name;
            cout << "Enter Roll Number of Student\n";
            cin >> Roll;
            cout << "Enter Course of Student \n";
            cin >> Course;
            cout << "Enter Total Marks of Student\n";
            cin >> Marks;
            Insert_Record(Roll, Name, Course, Marks);
        }
        else if (Choice == 2) {
            cout << "Enter Roll Number of Student whose "
                    "record is to be deleted\n";
            cin >> Roll;
            Delete_Record(Roll);
        }
        else if (Choice == 3) {
            cout << "Enter Roll Number of Student whose "
                    "record you want to Search\n";
            cin >> Roll;
            Search_Record(Roll);
        }
        else if (Choice == 4) {
            Show_Record();
        }
        else if (Choice == 5) {
            exit(0);
        }
        else {
            cout << "Invalid Choice "
                 << "Try Again\n";
        }
    }
    return 0;
}

C

/* P3.1 Program of single linked list of non integer type node*/

#include<stdio.h>
#include<conio.h>
#include<stdlib.h>
#include<string.h>
typedef struct student
{
    int roll_no;
    char name[100];
    float marks;
    struct student *next;
}node;
node *create_list();
void display(node *);
void count(node *);
void search(node *,int);
node *addatbeg(node *);
node *addatend(node *);
node *addafter(node *,int);
node *addbefore(node *,int);
node *addatpos(node *,int);
node *del(node *,int);
node *reverse(node *);

void main(){
    int choice,data,item,pos;
    node *start;
    start=NULL;
    do
    {
        printf("ENTER YOUR CHOICE\n");
        printf("1.Create List\n");
        printf("2.Display\n");
        printf("3.Count\n");
        printf("4.Search\n");
        printf("5.Add to empty list / Add at beginning\n");
        printf("6.Add at end\n");
        printf("7.Add after node\n");
        printf("8.Add before node\n");
        printf("9.Add at position\n");
        printf("10.Delete\n");
        printf("11.Reverse\n");
        printf("12.Quit\n\n");

        printf("Enter your choice : ");
        scanf("%d",&choice);

        switch(choice)
        {
         case 1:
            start=create_list();
            break;
         case 2:
            display(start);
            break;
         case 3:
            count(start);
            break;
         case 4:
            printf("Enter the element to be searched : ");
            scanf("%d",&data);
            search(start,data);
            break;
        case 5:
            start=addatbeg(start);
            break;
         case 6:
            start=addatend(start);
            break;
         case 7:
            printf("Enter the roll no after which to insert : ");
            scanf("%d",&item);
            start=addafter(start,item);
            break;
         case 8:

            printf("Enter the roll no before which to insert : ");
            scanf("%d",&item);
            start=addbefore(start,item);
            break;
         case 9:
            printf("Enter the position at which to insert : ");
            scanf("%d",&pos);
            start=addatpos(start,pos);
            break;
         case 10:
            printf("Enter the roll no to be deleted : ");
            scanf("%d",&data);
            start=del(start, data);
            break;
         case 11:
            start=reverse(start);
            break;
         case 12:
             exit(0);
         default:
             printf("Wrong choice\n");
        }/*End of switch */
    }while(choice!=12);/*End of while */
}/*End of main()*/
node *create_list()
{
    int roll,flag = 1;
    float marks;
    char Name[100];
    char ans='y';
    node *tem,*new,*start;
    node *getnode();
    tem=NULL;
    do
    {
        printf("Enter the roll number : ");
        scanf("%d",&roll);
        printf("Enter name of student : ");
        _flushall();
        gets(Name);
        printf("Enter the marks : ");
        scanf("%d",&marks);
        new=getnode();
        if(new==NULL)
        printf("\nMemory is not allocated : ");
        new->roll_no=roll;
        strcpy(new->name,Name);
        new->marks=marks;
        if(flag==1)
        {
            start=new;
            tem=start;
            flag=0;
        }
        else
        {
            tem->next=new;
            tem=new;
        }
    printf("\nDo you want to enter more elements(y/n) : ");
    ans=getche();
    } while (ans=='y');
    printf("\nThe single linked list is created\n");
    return start;
}/*End of create_list()*/
node *getnode()
{
    node *temp;
    temp=(node*)malloc(sizeof(node));
    temp->next=NULL;
    return temp;
}
void display(node *start)
{
    node *p;
    p=start;
    if(p==NULL)
    {
        printf("List is empty\n");
        return;
    }
    printf("List is :\n");
    while(p!=NULL)
    {
        _flushall();
        printf("%d|%s|%0.2f| \n",p->roll_no,p->name,p->marks);
        p=p->next;
    }
    printf("\n\n");
}/*End of display() */
void count(node *start)
{
    node *p;
    int cnt=0;
    p=start;
    while(p!=NULL)
    {
        p=p->next;
        cnt++;
    }
    printf("Number of elements are %d\n",cnt);
}/*End of count() */
void search(node *start,int data)
{
    node *p;
    p=start;
    int pos=1;
    while(p!=NULL)
    {
        if(p->roll_no==data)
        {
            printf("Item %d found at position %d\n",data,pos);
            return;
        }
        p=p->next;
        pos++;
    }
    printf("Item %d not found in list\n",data);
}/*End of search()*/
node *addatbeg(node *start)
{
    node *tmp,*new;
    new=getnode();
    printf("Enter the roll no : ");
    scanf("%d",&new->roll_no);
    printf("Enter the name : ");
    _flushall();
    gets(new->name);
    printf("Enter the marks : ");
    scanf("%f",&new->marks);
    if(start==NULL)
    start=new;
    else
    {
        tmp=start;
        new->next=tmp;
        start=new;
    }
    return start;
}/*End of addatbeg()*/
node *addatend(node *start)
{
    node *p,*tmp;
    p=getnode();
    printf("Enter the roll no : ");
    scanf("%d",&p->roll_no);
    printf("Enter the name : ");
    _flushall();
    gets(p->name);
    printf("Enter the marks : ");
    scanf("%f",&p->marks);
    if(start==NULL){
    start=p;
    return start;}
    else{
    tmp=start;
    while(tmp->next!=NULL)
        tmp=tmp->next;
    tmp->next=p;
    p->next=NULL;
    return start;}
}/*End of addatend()*/
node *addafter(node *start,int item)
{
    node *tmp,*p;
    p=getnode();
            printf("Enter the roll no : ");
            scanf("%d",&p->roll_no);
            printf("Enter the name : ");
            _flushall();
            gets(p->name);
            printf("Enter the marks : ");
            scanf("%f",&p->marks);
            if(start==NULL)
            start=p;
            else
            {
                tmp=start;
                do
                {
                    if(tmp->roll_no==item)
                    {
                    p->next=tmp->next;
                    tmp->next=p;
                    return start;
                    }
                    else
                    tmp=tmp->next;
                }while(tmp!=NULL);
            }
}/*End of addafter()*/
node *addbefore(node *start,int item)
{
    node *tmp,*p;
    if(start==NULL )
    {
        printf("List is empty\n");
        return start;
    }
    /*If data to be inserted before first node*/
    if(start->roll_no==item)
    {
        tmp=getnode();
        printf("Enter the roll no : ");
        scanf("%d",&tmp->roll_no);
        printf("Enter the name : ");
        gets(tmp->name);
        printf("Enter the marks : ");
        scanf("%f",&tmp->marks);
        tmp->next=start;
        start=tmp;
        return start;
    }
    p=start;
    while(p->next!=NULL)
    {
        if(p->next->roll_no==item)
        {
            tmp=getnode();
            printf("Enter the roll no : ");
            scanf("%d",&tmp->roll_no);
            printf("Enter the name : ");
            gets(tmp->name);
            printf("Enter the marks : ");
            scanf("%f",&tmp->marks);
            tmp->next=p->next;
            p->next=tmp;
            return start;
        }
        p=p->next;
    }
    printf("%d not present in the list\n",item);
    return start;
}/*End of addbefore()*/
node *addatpos(node *start,int pos)
{
    node *tmp,*p;
    int i;
    tmp=getnode();
    printf("Enter the roll no : ");
    scanf("%d",&tmp->roll_no);
    printf("Enter the name : ");
    gets(tmp->name);
    printf("Enter the marks : ");
    scanf("%f",&tmp->marks);
    if(pos==1)
    {
        tmp->next=start;
        start=tmp;
        return start;
    }
    p=start;
    for(i=1; i<pos-1 && p!=NULL; i++)
        p=p->next;
    if(p==NULL)
        printf("There are less than %d elements\n",pos);
    else
    {
        tmp->next=p->next;
        p->next=tmp;
    }
    return start;
}/*End of addatpos()*/
node *del(node *start,int data)
{
    node *tmp,*p;
    if(start==NULL)
    {
        printf("List is empty\n");
        return start;
    }
    /*Deletion of first node*/
    if(start->roll_no==data)
    {
        tmp=start;
        start=start->next;
        free(tmp);
        return start;
    }
    /*Deletion in between or at the end*/
    p=start;
    while(p->next!=NULL)
    {
        if(p->next->roll_no==data)
        {
            tmp=p->next;
            p->next=tmp->next;
            free(tmp);
            return start;
        }
        p=p->next;
    }
    printf("Element %d not found\n",data);
    return start;
}/*End of del()*/
node *reverse(node *start)
{
    node *prev, *ptr, *n;
    prev=NULL;
       ptr=start;
    while(ptr!=NULL)
    {
        n=ptr->next;
        ptr->next=prev;
        prev=ptr;
        ptr=n;
    }
    start=prev;
    return start;
}/*End of reverse()*/

Output: Below is the screenshots of the output of the various functions provided by the student record management system:

• Create Record:
  

• Show Record:
  

• Delete Record:
  

• Search Record:
  

• Student Record: