How to print student records according to specific marks entered

Question

I have problem regarding searching student records based on the mark I enter. for example I want to search students who is their mark are = 12. And then display their records upon that search. how is that possible I hope You can help

Here is the full code

// 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 "
             << "Avialable\n";
        return;
    }
  
    // Otherwise
    else {
        Node* p = head;
        while (p) {
            if (p->roll == roll) {
                cout << "Roll Nmuber\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 "
                 << "Avialable\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;
}

I have done all functions, but couldn't know how to add this sort of search. I would be appreciated if you help

Who taught you `#include `? Please [don't do that](https://stackoverflow.com/questions/31816095/why-should-i-not-include-bits-stdc-h). Also, `using namespace std;` is [a bad habit](https://stackoverflow.com/questions/1452721/why-is-using-namespace-std-considered-bad-practice), as are global variables. — Some programmer dude, Mar 24 '21 at 15:04
It seems to me that you could use [a couple of good books](https://stackoverflow.com/questions/388242/the-definitive-c-book-guide-and-list) to learn C++ properly. Right now it's not that much different from C, and with many small but serious mistakes. — Some programmer dude, Mar 24 '21 at 15:10
`Node* head = new Node();` certainly isn't helping, specially since you rely on `head` being `NULL` in multiple places where you determine the list is empty. And fyi, `Node* t = new Node;t = head;` is an *instant* memory leak in two lines of code. C++ isn't Java or C#. A good book and better understanding of pointers is probably on the agenda. — WhozCraig, Mar 24 '21 at 15:10
IMHO, in your insert method, you should be checking for duplicates as you find the appropriate insertion point. Presently, you traverse the list twice, once with `check` and then in the insert method. Get a good book on data structures. — Thomas Matthews, Mar 24 '21 at 15:20
Usually, menu processing or selection processing is best with a `switch` statement. — Thomas Matthews, Mar 24 '21 at 15:22

score 0 · Accepted Answer · answered Mar 24 '21 at 15:34

Apart from the remarks you have already been told in comments, searching students having a given mark is there. Just look at the Show_Record() function:

you browse the full list
you display records

If you simply add a if (p->Marks == value) in your loop, it is done:

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

thanks bro it somehow worked for me, but i want to display students who got 20 marks, how is that can be done? — Ahmed Sheikh, Mar 24 '21 at 16:41

How to print student records according to specific marks entered

1 Answers1