Queue using linked list

#include<stdio.h>

#include<conio.h>

#include<alloc.h>

struct node

{

int data;

struct node *next;

};

void main()

{

struct node *front,*rear,*tp,*temp;

int ch,key,value;

clrscr();

front = rear = NULL;

do

{

printf("1.Insert @ last\t ");

printf("2.Delete @ first\t 3.Display");

printf("\n\nEnter your choice:");

scanf("%d",&ch);

switch(ch)

{

case 1:  {

             printf("\nenter a no to insert @ last:");

             temp=(struct node*)malloc(sizeof(struct node));

             scanf("%d",&value);

             temp->data=value;

             temp->next=NULL;

             if(rear==NULL&& front==NULL)

             {

             rear=temp;

             front=temp;

             }

             else

             {

              tp=rear;

              while(tp->next!=NULL)

              {

              tp=tp->next;

              }

              tp->next=temp;

              }}

             break;

 case 2: {

              if(front==NULL)

              printf("\n list is empty");

              else

              {

              tp=front;

              front=front->next;

              free(tp);

              }

             }break;

 case 3: {

             if(rear==NULL)

             printf("\nlist is empty");

             else

             {

             tp=front;

             printf("\nvalues are:\n");

             while(tp!=NULL)

             {

             printf("%d\t",tp->data);

             tp=tp->next;

             }

             }

             break;

default: printf("\nenter correct choice");

             break;

}}

}while(ch<4);

getch();

}