Answer to Question #250295 in C for Buzz

Question

Create three database using header linked list

              Student  (Roll No, Name, Branch ID, CGPA)

              University  (University ID, University Name, University Location, Year of start)

              Branch  (Branch ID, University ID, Branch Name)

Implement the following modules/ sub-modules using menu driven approach:

-> Display the list of Branches available in any given University

-> Display the University details in ascending order of their year of starting

-> Display the all Student name/ all University name for a given name substring entered by the user.

Answer 1

#include <conio.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
int count = 0;
struct node {
    struct node* prev;
    int ssn;
    long int phno;
    float sal;
    char name[20], dept[10], desg[20];
    struct node* next;
} * h, *temp, *temp1, *temp2, *temp4;
void create()
{
    int ssn;
    long int phno;
    float sal;
    char name[20], dept[10], desg[20];
    temp = (struct node*)malloc(sizeof(struct node));
    temp->prev = NULL;
    temp->next = NULL;
    printf("\n enter ssn, name, depart"
           "ment, designation, salary "
           "and phno of employee:\n");
    scanf("%d %s %s %s %f %ld",
          &ssn, name, dept, desg,
          &sal, &phno);
    temp->ssn = ssn;
    strcpy(temp->name, name);
    strcpy(temp->dept, dept);
    strcpy(temp->desg, desg);
    temp->sal = sal;
    temp->phno = phno;
    count++;
}
void insertbeg() {
    if (h == NULL) {
        create();
        h = temp;
        temp1 = h;
    }
    else {
        create();
        temp->next = h;
        h->prev = temp;
        h = temp;
    }
}
void insertend() {
    if (h == NULL) {
        create();
        h = temp;
        temp1 = h;
    }
    else {
        create();
        temp1->next = temp;
        temp->prev = temp1;
        temp1 = temp;
    }
}
void displaybeg()
{
    temp2 = h;
    if (temp2 == NULL) {
        printf("\n list is empty\n");
        return;
    }
    printf("\n linked list elements "
           "from beginning:\n");
    while (temp2 != NULL) {
        printf("%d %s %s %s %f %ld\n",
               temp2->ssn, temp2->name,
               temp2->dept, temp2->desg,
               temp2->sal, temp2->phno);
        temp2 = temp2->next;
    }
    printf("number of employees=%d", count);
}
int deleteend()
{
    struct node* temp;
    temp = h;
    if (temp == NULL) {
        printf("list is empty\n");
        return 0;
    }
    if (temp->next == NULL) {
        printf("%d %s %s %s %f %ld\n",
               temp->ssn, temp->name,
               temp->dept, temp->desg,
               temp->sal, temp->phno);
        free(temp);
        h = NULL;
    }
    else {
        temp = temp1;
        temp2 = temp1->prev;
        temp2->next = NULL;
        printf("%d %s %s %s %f %ld\n",
               temp->ssn, temp->name,
               temp->dept, temp->desg,
               temp->sal, temp->phno);
        free(temp);
        temp1 = temp2;
    }
    count--;
    return 0;
}
int deletebeg()
{
    struct node* temp;
    temp = h;
    if (temp == NULL) {
        printf("list is empty\n");
        return 0;
    }
    if (temp->next == NULL) {
        printf("%d %s %s %s %f %ld\n",
               temp->ssn, temp->name,
               temp->dept, temp->desg,
               temp->sal, temp->phno);
        free(temp);
        h = NULL;
    }
    else {
        h = h->next;
        h->prev = NULL;
        printf("%d %s %s %s %f %ld\n",
               temp->ssn, temp->name,
               temp->dept, temp->desg,
               temp->sal, temp->phno);
        free(temp);
    }
    count--;
    return 0;
}
void employerDetails() {
    int ch, n, i;
    h = NULL;
    temp = temp1 = NULL;
    printf("--------Menu------------\n");
    printf("\n 1.create a DLL of n emp");
    printf("\n 2.display from beginning");
    printf("\n 3.insert at end");
    printf("\n 4.delete at end");
    printf("\n 5.insert at beginning");
    printf("\n 6.delete at beginning");
    printf("\n 7.to show DLL as queue");
    printf("\n 8.exit\n");
    printf("----------------------\n");
    while (1) {
        printf("\n enter choice : ");
        scanf("%d", &ch);
        switch (ch) {
            case 1:
                printf("\n enter number of employees:");
                scanf("%d", &n);
                for (i = 0; i < n; i++)
                    insertend();
                break;
            case 2:
                displaybeg();
                break;
            case 3:
                insertend();
                break;
            case 4:
                deleteend();
                break;
            case 5:
                insertbeg();
                break;
            case 6:
                deletebeg();
                break;
            case 7:
                printf("\n to show DLL as queue \n1.perform insert and deletion operation by calling insertbeg() and deleteend() respectively\n \t OR \n 2.perform insert and delete operations by calling insertend() and deletebeg() respectively\n");
                break;
            case 8:
                exit(0);
            default:
                printf("wrong choice\n");
        }
    }
}

int main() {
    employerDetails();
    return 0;
}