queue_array.c

#include<stdlib.h>
#include<stdio.h>
#define size 50

int Q[size], rear=-1,front=0;

int isempty() {
	if(front == -1 || front > rear)
		return 1;
	else
		return 0;
}

int isfull() {
	if(rear == size - 1)
		return 1;
	else
		return 0;
}

void InsertQ(int item) {
	if(isfull())
		printf("Queue is Full");
	else {
		if(front == -1)
			front = 0;
			rear = rear+1;
			Q[rear] = item;
	}
	
}

int DeleteQ() {
	int index = -1;
	if(isempty()) {
		printf("Queue is empty");
	}
	else {
		index = front++;
	}
	return index;
}

void Display() {

	if(isempty()){
		printf("Queue is empty");
	}
	int i;
	printf("\n Queue :");
	for (i = front; i != rear+1; i = (i + 1) % size) {
		printf("%d ", Q[i]);
	}
}

int main() {
	int ch;
	printf("Queue");
	do {
		printf("\n1. Insert 2. Delete 3.Display 4.Exit \n");
		scanf("%d",&ch);
		switch(ch) {
			case 1: {
				int item;
				printf("Item to be entered : ");
				scanf("%d",&item);
				InsertQ(item);
				break;
			}
			case 2: {
				int val = DeleteQ();
				if(val != -1)
					printf("The deleted item is %d",Q[val]);
				break;
			} 
			case 3: 
                Display(); 
                break;
			case 4: 
                exit(0);
		}
	} while(1);
	return 0;
}