Queue using Array in C program.

queue-using-array.c

#include<stdio.h>
#include<stdlib.h>
#define MAX 5

int front = 0;
int last = 0;
int queue[MAX];

void enqueue(int val) {		 
	queue[last++] = val;
	printf("Value added to the queue\n");
}

int dequeue() {
	int temp = queue[front];
	front++;
	return temp;
}

int checkFull() {
	if(last == MAX-1) {
		printf("Queue is Full!\n");
		return 0;
	}
	return 1;
}

int checkEmpty() {
	if(front == last) {
		printf("Queue is Empty!\n");
		return 0;
	}
	return 1;
}

void display() {
	int i=front;
	int j=last;	
	for(;i<j;i++) {
		printf("-> %d\n", queue[i]);
	}
}

int main() {
	int choice = 0;
	int value = 0;
	while(1) {
		printf("1. Enqueue\n2. Dequeue\n3. Display\n4. Exit\n >>> ");
		scanf("%d", &choice);
		switch(choice) {
			case 1:
				if(checkFull()) {
					printf("Enter the Number to Enqueue >> ");
					scanf("%d", &value);
					enqueue(value);
				}
				break;
			case 2:
				if(checkEmpty()) {
					printf("Dequeued element is %d\n", dequeue());
				}
				break;
			case 3:
				if(front != last) {
					display();
				}
				break;
			case 4:
				exit(0);
				break;
			default:
				printf("Wrong Choice!\n");
				exit(0);	
		}
	}
	return 0;
}