Using dynamic variables and pointers Write a C program to construct a singly linked list consisting of the following information in each node; Roll – No (Integer), Name (Character string)

#include<stdio.h>
#include<conio.h>
#include<string.h>
#include<stdlib.h>
#define NULL 0
create();
display();
del_item(int);
ins_beg();
search(int);
struct node
{
 int rollno;
 char name[20];
 struct node *link;
 } *start=NULL,*p,*q,*prev;
 int regno,rno;
 char str[20];
 void main()
 {
  int ch,i;
  clrscr();
  while(1)
  {
   printf("\n 1.create a linked list ");
   printf("\n 2.insertion of node in front of the list ");
   printf("\n 3.deletion of node based on rollno");
   printf("\n 4.searching a node based on rollno");
   printf("\n 5.display linked list ");
   printf("\n 6.exit");
   printf("\n enter your choice:");
   scanf("%d",&ch);
   switch(ch)
   {
    case 1:create();
    break;
    case 2:printf("\n linked list before insertion\n");
    display();
    ins_beg();
    printf("\n linked list after insertion\n");
    display();
    break;
    case 3:printf("\n enter the item to be deleted:");
    scanf("%d",&regno);
    del_item(regno);
    printf("\n linked list after deletion");
    display();
    break;
    case 4:printf("\n searching for an node based on rollno");
       scanf("%d",&rno);
       search(rno);
       break;
    case 5:display();
        break;
    case 6:exit(0);
    default:printf("\n error in choice");
    }
    }
    }
    create()
    {
     char choice='y';
     clrscr();
     start=NULL;
     q=start;
     while(choice=='y')
     {
      p=malloc(sizeof(struct node));
      printf("\n enter the register number :");
      scanf("%d",&regno);
      printf("\n enter the student name:");
      scanf("%s",str);
      p->rollno=regno;
      strcpy(p->name,str);
      p->link=NULL;
      if(start==NULL)
      {
       start=p;
       q=p;
       }
       else
       {
    q->link=p;
    q=p;
    }
       printf("\n do you want to create another node (y/n");
       choice=getch();
       }
       return 0;
       }
       display()
       {
       printf("\n the elements are");
       p=start;
       while(p!=NULL)
       {
    printf("\n register number :%d",p->rollno);
    printf("\n NAME :%s",p->name);
    p=p->link;
    }
    getch();
       return 0;
       }
       ins_beg()
       {
    printf("\n enter register number:");
    scanf("%d",&regno);
    printf("\n enter name of the student:");
    scanf("%s",str);
    p=malloc(sizeof(struct node));
    p->rollno=regno;
    strcpy(p->name,str);
    p->link=start;
    start=p;
    return 0;
       }
       del_item(int regno)
       {
    p=start;
       prev=NULL;
       if(start==NULL)
       {
    printf("\n linked list is empty");
    return 0;
    }
    if(start->rollno==regno)
    {
    start=start->link;
    free(p);
    return 0;
    }
       while((p->rollno!=regno)&&(p!=NULL))
       {
    prev=p;
    p=p->link;
       }
       if(p==NULL)
       printf("\n register number %d is not found in the linked list \n",regno);
       else
       prev->link=p->link;
       return 0;
       }
       search(int rno)
       {
    int i=0;
    p=start;
    while(p!=NULL)
    {
     if(rno==p->rollno)
     {
          i++;
          printf("\n node found at position %d",i);
          printf("register number:%d",p->rollno);
          printf("\n name:%s",p->name);
          }
          else
          {
          p=p->link;
          i++;
          }
     }
     printf("\n node with register number %d does not exist",regno);
     return 0;
    }