Queue using linked list
#include <iostream>
using namespace std;
struct Node
{
int data;
struct Node *next;
}*front = NULL, *rear = NULL;
void enQueue(int value)
{
struct Node *newNode;
newNode = (struct Node*)malloc(sizeof(struct Node));
newNode -> data = value;
newNode -> next = NULL;
if (front == NULL)
front = rear = newNode;
else {
rear -> next = newNode;
rear = newNode;
}
cout<<"\nInsertion is Successful\n";
}
void deQueue()
{
if (front == NULL)
cout<<"\nUnderflow. Queue is Empty\n";
else
{
struct Node *temp = front;
front = front -> next;
cout<<"\nDeleted element: \n";
cout<< temp -> data;
free(temp);
}
}
void display()
{
if (front == NULL)
cout<<"\nQueue is Empty!\n";
else {
struct Node *temp = front;
while (temp != NULL) {
cout<<"--->";
cout<< temp -> data;
temp = temp -> next;
}
cout<<"-->NULL\n";
}
}
int main()
{
int choice, value;
while(1) {
cout<<"1. Insert\n2. Delete\n3. Display\n4. Exit\n";
cout<<"Enter your choice: ";
cin>>choice;
switch(choice) {
case 1: cout<<"Enter the value to be inserted: ";
cin>>value;
enQueue(value);
break;
case 2: deQueue();
break;
case 3: display();
break;
case 4: exit(0);
default: cout<<"\nWrong choice. Please try again\n";
}
}
}
