linear_queue.c

/*Program for implementing a linear queue*/
#include<stdio.h> 
#include<stdlib.h> 

#define MAX 10

int queue_arr[MAX];
int rear = -1;
int front = -1;

void insert(int item);
int del();
int peek();
void display();
int isFull();
int isEmpty();

int main()
	{
		int choice,item; 
		while(1)
		{
			printf("1.Enqueue\n");
			printf("2.Dequeue\n");
			printf("3.isFull\n");
			printf("4.isEmpty\n");
			printf("5.Display\n");
			printf("6.Quit\n"); 
			printf("Enter your choice : "); 
			scanf("%d",&choice); 
			switch(choice)
			{
				case 1:
				printf("Input the element for adding in queue : "); 
				scanf("%d",&item);
				insert(item);
				break;
				
				case 2:
				item=del();
				printf("Deleted element is %d\n",item); 
				break;
				
				case 3:
				if((isFull())==0)
					printf("Overflown: False\n"); 
				else
					printf("Overflown: True\n"); 
				break;
				
				case 4:
				if((isEmpty())==0)
					printf("Not Empty\n");
				else
					printf("Empty\n");
				break;
				
				case 5:
				display();
				break;
				
				case 6:
				exit(1);
				break;
				
				default:
				printf("Wrong choice\n")
			}/*End of switch*/
		}/*End of while*/
	}/*End of main()*/

void insert(int item) 
{
	if(isFull()) 
		{
			printf("Queue Overflow\n");
			return; 
		}
	if(front==-1) 
		front=0; 
	rear=rear+1;
	queue_arr[rear] = item;
}/*End of insert()*/

int del()
{
	int item;
	if(isEmpty())
		{
			printf("Queue Underflow\n"); exit(1);
		}
	item = queue_arr[front];
	front=front+1;
	return item;
}/*End of del()*/

int isEmpty() 
{
	if(front == -1 || front == rear+1) 
		return 1;
	else
		return 0;
}/*End of isEmpty()*/ 

int isFull()
{
	if(rear == MAX-1)
		return 1;
	else
		return 0;
}/*End of isFull()*/

void display()
{
	int i;
	if(isEmpty())
	{
		printf("Queue is empty\n");
		return;
	}
	printf("Queue is: \n\n");
	for(i=front; i<=rear; i++)
		printf("%d ",queue_arr[i]);
	printf("\n\n");
}/*End of display*/