Circular Queue in C

Hello guys

#include<stdio.h>
#define MAX 5
int queue[MAX], front = -1, rear = -1;

void disp()
{
	int i;
	if(front==-1&&rear==-1)
	{
		printf("\n Queue is empty!!!");
	}
	else
	{
		if(front<=rear)
		{
			printf("\n The queue elements are :");
			for(i = front; i<=rear; i++)
			{
				printf("%d ",queue[i]);
			}
		}
		else
		{
			printf("\n The queue elements are :");
			for(i =front; i<MAX; i++ )
				printf("%d ",queue[i]);
			for(i =0; i<=rear; i++ ) 
				printf("%d ",queue[i]);
		}
	}	
}


void enqueue(int val)
{
	//circulated and filled
	if( front == rear+1 )
		printf("\n Overflow");
	// filled like linear queue
	else if( front == 0 && rear == MAX-1 )
		printf("\n Overflow");
	// the whole queue is empty
	else if( rear == -1 && front == -1 )
	{
		rear = 0;
		front = 0;
		queue[rear] = val;
		printf("\n %d successfully enqueued!!!",val);
		disp();
	}
	//rear has reached to last position and front[0] is empty  
	else if(rear == MAX-1 && front!=0)
	{
		rear = 0;
		queue[rear] = val;
		printf("\n %d successfully enqueued!!!",val);
		disp();
	}
	// normal insertion
	else
	{
		rear++;
		queue[rear] = val;
		printf("\n %d successfully enqueued!!!",val);
		disp();
	}	
}

void dequeue()
{
	int x;
	// queue is empty
	if(rear == -1 && front == -1)
		printf("\n Underflow");
	// only one element
	else if(front == rear)
	{
		x = queue[front]; 
		front = -1;
		rear = -1; 
		printf("\n %d successfully dequeued",x);
		disp();
	}
	// end element
	else if(front == MAX-1 )
	{
		x = queue[front];
		front = 0;
		printf("\n %d successfully dequeued",x);
		disp();
	}
	// normal deletion
	else
	{
		x = queue[front];
		front++;
		printf("\n %d successfully dequeued",x);
		disp();
	} 
}


void main()
{
	int ch,e;
	do
	{
		printf("\n===MENU===");
		printf("\n 1. ENQUEUE");
		printf("\n 2. DEQUEUE");
		printf("\n 3. DISPLAY");
		printf("\n 4. EXIT");
		printf("\n Enter your choice : ");
		scanf("%d",&ch);
		switch(ch)
		{
			case 1 : if((front == 0 && rear == MAX-1) || (front == rear+1) )
						printf("\n Element cannot be inserted \n Queue overflow");
					 else{
					 printf("\n Enter the element : ");
					 scanf("%d",&e);
					 enqueue(e);}
					 break;
			case 2 : dequeue();
					 break;
			case 3 : disp();
					 break;
			case 4 : printf("\n Thank you!!! \n ");
					 break;
			default : printf("\n Invalid Input ");
					 break;
		}
	
	}while(ch!=4);
}

/*
OUTPUT :
===MENU===
 1. ENQUEUE
 2. DEQUEUE
 3. DISPLAY
 4. EXIT
 Enter your choice : 1

 Enter the element : 56

 56 successfully enqueued!!!
 The queue elements are :56 
===MENU===
 1. ENQUEUE
 2. DEQUEUE
 3. DISPLAY
 4. EXIT
 Enter your choice : 1

 Enter the element : 27

 27 successfully enqueued!!!
 The queue elements are :56 27 
===MENU===
 1. ENQUEUE
 2. DEQUEUE
 3. DISPLAY
 4. EXIT
 Enter your choice : 1

 Enter the element : 44

 44 successfully enqueued!!!
 The queue elements are :56 27 44 
===MENU===
 1. ENQUEUE
 2. DEQUEUE
 3. DISPLAY
 4. EXIT
 Enter your choice : 1

 Enter the element : 48

 48 successfully enqueued!!!
 The queue elements are :56 27 44 48 
===MENU===
 1. ENQUEUE
 2. DEQUEUE
 3. DISPLAY
 4. EXIT
 Enter your choice : 1

 Enter the element : 29

 29 successfully enqueued!!!
 The queue elements are :56 27 44 48 29 
===MENU===
 1. ENQUEUE
 2. DEQUEUE
 3. DISPLAY
 4. EXIT
 Enter your choice : 1

 Element cannot be inserted 
 Queue overflow
===MENU===
 1. ENQUEUE
 2. DEQUEUE
 3. DISPLAY
 4. EXIT
 Enter your choice : 2

 56 successfully dequeued
 The queue elements are :27 44 48 29 
===MENU===
 1. ENQUEUE
 2. DEQUEUE
 3. DISPLAY
 4. EXIT
 Enter your choice : 1

 Enter the element : 2

 2 successfully enqueued!!!
 The queue elements are :27 44 48 29 2 
===MENU===
 1. ENQUEUE
 2. DEQUEUE
 3. DISPLAY
 4. EXIT
 Enter your choice : 3

 The queue elements are :27 44 48 29 2 
===MENU===
 1. ENQUEUE
 2. DEQUEUE
 3. DISPLAY
 4. EXIT
 Enter your choice : 2

 27 successfully dequeued
 The queue elements are :44 48 29 2 
===MENU===
 1. ENQUEUE
 2. DEQUEUE
 3. DISPLAY
 4. EXIT
 Enter your choice : 2