Insert a node at the beginning of the list

Write a Program in C to Insert a node at the beginning of the list

# include <stdio.h>
#include<conio.h>
# include <malloc.h>
void create(int num);
void display();
void insert_begin();
struct node
{
int data;
struct node *addr_next;
}*start,*q,*tmp;
void main()
{
int action,n,i;
char choice='y';
start=NULL;
clrscr();
while(1)
{
printf("1) Create Linked List\n");
printf("2) Insert at Beginning\n");
printf("3) Display\n");
printf("4) Exit\n");
printf("Enter your choice : ");
scanf("%d",&action);
switch(action)
{
case 1:
choice='y';
while(choice=='y'||choice=='Y')
{
printf("\nEnter a number : ");
scanf("%d",&n);
create(n);
printf("\n");
display();
printf("\t\t\t\t\t\t\t\tContinue ? ");
scanf(" %c",&choice);
}
getch();
break;
case 2:
choice='y';
while(choice=='y'||choice=='Y')
{
printf("\nEnter a number : ");
scanf("%d",&n);
insert_begin(n);
printf("\n");
display();
printf("\t\t\t\t\t\t\t\tContinue ? ");
scanf(" %c",&choice);
}
getch();
break;
case 3:
display();
break;
case 4:
exit();
}
}
}
void create(int num)
{
tmp=malloc(sizeof(struct node));
tmp->data=num;
tmp->addr_next=NULL;
if(start==NULL) //check if 1st element
{
start=tmp; //point start at tmp
}
else //not 1st element
{
q=start; //point q at start
while(q->addr_next!=NULL) //go to end of linked list
{
q=q->addr_next;
}
q->addr_next=tmp; //store address
}
}
void insert_begin(int num)
{
tmp=malloc(sizeof(struct node));
tmp->data=num;
tmp->addr_next=start;
start=tmp;
}
void display()
{
if(start == NULL) //linked list is empty
{
printf("List is empty\n");
}
else
{
q=start; //point q at start
while(q!=NULL) //go to end of linked list
{
printf("| %d | %d | --> ", q->data,q->addr_next);
q=q->addr_next;
}
printf("\n\n");
}
}