Linear Queue Implementation

/*
Linear Queue Impmelaintaction
*/
 
#include<stdio.h>
#define N 5
 
int queue[N];
int front=-1,rear=-1;
 
void enque();
void deque();
void display();
void peek();
 
int main(){
	int choice;
	do{
		printf("\n***Queue Operations***\n");
		printf("1. Enque\n");
		printf("2. Deque\n");
		printf("3. Peek\n");
		printf("4. Display\n");
		printf("0 To Exit\n");
		printf("Enter Choice");
		scanf("%d",&choice);
		switch(choice){
			case 1:
				enque();
				break;
			case 2:
				deque();
				break;
			case 3:
				peek();
				break;
			case 4:
				display();
				break;
			default:
				printf("\n!!Wrong choice!!\n");
		}
	}while(choice!=0);
	return 0;
}
 
void enque(){
	int x;
	if(rear==N-1){
		printf("\noverflow\n");
	}
	else if(front==-1 && rear==-1){
		front++;
		rear++;
		printf("Enter x ");
		scanf("%d",&x);
		queue[rear]=x;
	}
	else{
		rear++;
		printf("Enter x ");
		scanf("%d",&x);
		queue[rear]=x;
	}
}
 
void deque(){
	if(front==-1&&rear==-1){
		printf("\nQueue is Empty\n");
	}
	else if(front==rear){
		front=rear=-1;
		printf("\nDeleted successfully\n");
	}
	else{
		front++;
		printf("\nDeleted successfully\n");
	}
}
 
void peek(){
	if(front==-1 && rear==-1){
		printf("\n Queue is Empty\n");
	}
	else{
		printf("%d",queue[front]);
	}
}
 
void display(){
	int i;
	if(front==-1 && rear==-1){
		printf("\nQueue is Empty\n");
	}
	else{
		for(i=front;i<=rear;i++){
			printf("%d ",queue[i]);
		}
	}
}

OUTPUT