#include <stdio.h>
#include <stdlib.h>
struct node {
int data;
struct node *next; // Pointer to the next node
};
// Function declarations
void create(struct node **front);
void enqueue(struct node **front, int val);
int dequeue(struct node **front);
void display(struct node **front);
int main() {
struct node *front; // Front pointer for the queue
int choice, val;
create(&front); // Initialize the queue
while(1) {
printf("\n\n<<< MENU >>>");
printf("\n1. Create\n2. Enqueue\n3. Dequeue\n4. Display\n5. Exit");
printf("\nEnter your choice: ");
scanf("%d", &choice);
switch(choice) {
case 1:
create(&front);
printf("\nQueue created successfully!");
break;
case 2:
printf("\nEnter value to insert: ");
scanf("%d", &val);
enqueue(&front, val);
printf("\nValue inserted successfully!");
break;
case 3:
val = dequeue(&front);
if(val == -999)
printf("\nQueue is empty!");
else
printf("\n%d removed successfully!", val);
break;
case 4:
display(&front);
break;
case 5:
exit(0);
default:
printf("\nInvalid choice!");
}
}
return 0;
}
// Initialize the queue (set front to NULL)
void create(struct node **front) {
*front = NULL;
}
// Add an element to the queue (enqueue)
void enqueue(struct node **front, int val) {
struct node *temp = (struct node *)malloc(sizeof(struct node));
struct node *p;
temp->data = val;
temp->next = NULL;
if (*front == NULL) {
*front = temp; // If queue is empty, make temp the first node
} else {
p = *front;
while (p->next != NULL) {
p = p->next; // Traverse to the last node
}
p->next = temp; // Add the new node to the end
}
}
// Remove an element from the queue (dequeue)
int dequeue(struct node **front) {
struct node *temp = *front;
int x;
if (temp == NULL) {
return -999; // Return -999 if the queue is empty
} else {
x = temp->data; // Get the data of the front node
*front = temp->next; // Move the front pointer to the next node
free(temp); // Free the memory of the removed node
return x; // Return the data of the removed node
}
}
