#include<stdio.h>
#include<stdlib.h>
struct node
{
int data;
struct node *next;
};
typedef struct node node;
node *front;
node *rear;
void insert();
void del();
void display();
int main ()
{
int choice;
while(choice != 4)
{
printf("\n ---Main Menu--- \n");
printf("\n 1.Insert an element\n 2.Delete an element\n 3.Exit\n ");
printf("\n Enter your choice (1-3) :");
scanf("%d", &choice);
switch(choice)
{
case 1: insert();
display();
break;
case 2: del();
display();
break;
case 3: exit(0);
break;
default: printf("\n Invalid Choice ! \n");
}
}
}
void insert()
{
struct node *ptr;
int item;
ptr = (struct node *) malloc (sizeof(struct node));
if(ptr == NULL)
{
printf("\n OVERFLOW \n");
return;
}
else
{
printf("\n Enter value : \n");
scanf("%d", &item);
ptr -> data = item;
if(front == NULL)
{
front = ptr;
rear = ptr;
front -> next = NULL;
rear -> next = NULL;
}
else
{
rear -> next = ptr;
rear = ptr;
rear->next = NULL;
}
}
}
void del()
{
struct node *ptr;
if(front == NULL)
{
printf("\n UNDERFLOW \n");
return;
}
else
{
printf("\n %d is Deleted ", front -> data);
ptr = front;
front = front -> next;
free(ptr);
}
}
void display()
{
struct node *ptr;
ptr = front;
if(front == NULL)
{
printf("\n Queue is Empty !! ");
}
else
{ printf("\n Queue :\n");
while(ptr != NULL)
{
printf(" %d ", ptr -> data);
ptr = ptr -> next;
}
}
printf("\n");
}