queue.c

#include<stdio.h>
#include<stdlib.h>

#define MAX 50 
int queue[MAX], front = -1, rear = -1; 

void enqueue() {
int elem;
if (rear == MAX - 1) {
printf("Queue Overflow! Cannot enqueue more elements.\n");
return;
}
printf("Enter the element to be enqueued: ");
scanf("%d", &elem);
if (front == -1) {
front = 0; 
}
rear++; 
queue[rear] = elem; 
printf("%d enqueued to the queue.\n", elem);
}
 
 
void dequeue() {
if (front == -1 || front > rear) {
printf("Queue Underflow! No elements to dequeue.\n");
return;
}
printf("Dequeued element: %d\n", queue[front]);
front++; 
if (front > rear) {
front = rear = -1;
}
}


void display() {
int i;
if (front == -1) {
printf("Queue is empty.\n");
return;
}
printf("Queue elements are:\n");
for (i = front; i <= rear; i++) {
printf("%d ", queue[i]);
}
printf("\n");
}


int main()
    {
   int ch;
   while(1)
  {
  printf("\n---QUEUE MENU:---\n");
  printf("1.Enqueue\n");
  printf("2.Dequeue\n");
  printf("3.Display\n");
  printf("4.Exit\n");
  printf("Enter your choice: ");
  scanf("%d",&ch);
 switch(ch)
   {
   case 1: enqueue();
   
   break;
   
   case 2: dequeue();
   
   break;
   
   case 3: display();
   
   break;
   
   case 4: exit(0);
   
   default: printf("Invalid entry make a correct entry between 1-4");
    }
   
   }
    return 0;
     }