#include<stdio.h>
struct node{
int data;
struct node *next;
};
struct node *front=NULL,*rear=NULL,*newnode,*ptr;
int value;
void insert( ){
newnode = (struct node*)malloc(sizeof(struct node));
if(newnode==NULL){
printf("Queue Overflow.");
return;
}
printf("Enter a Value:");
scanf("%d",&value);
newnode->data = value;
newnode->next = NULL;
if(front==NULL)
front=rear=newnode;
else{
rear->next = newnode;
rear=newnode;
}
}
void del( ){
if(front==NULL)
printf("Queue underflow.");
else{
ptr=front;
printf("%d is deleted.", ptr->data);
if(front==rear)
front=rear=NULL;
else
front=front->next;
free(ptr);
}
}
void display( ){
if(front==NULL){
printf("Queue is Empty.");
return;
}
printf("\nQueue is: ");
for(ptr=front;ptr!=NULL;ptr=ptr->next)
printf("%d ",ptr->data);
}
void main(){
int ch;
while(1){
printf("\nQueue using Linked List");
printf("\n1. Insert\n2. Delete\n3. Display\n4. Exit");
printf("\nEnter your choice:");
scanf("%d",&ch);
switch(ch){
case 1: insert( ); break;
case 2: del( ); break;
case 3: display( ); break;
case 4: exit(0);
default: printf("Invalid Choice..");
}
}
}