Stack and Queue / Session XI

Stack 2 : Array Implementation : Push and Pop

Consider implementing a dynamically sized stack using an array.

Create a structure

struct stack

{

int * a;

int top;

int maxSize;

};

The structure stack has a pointer 'a' to a dynamically allocated array (used to hold the contents of the stack), an integer 'maxSize' that holds the size of this array (i.e the maximum number of data that can be held in this array) and an integer 'top' which stores the array index of the top element in the stack.

 Array Implementation answers 

click the link below for code:

    "Stack-and-queue-hands-on-session-XI-Q1.html"

Queue 1 : Array Implementation

Consider implementing a fixed size queue of maximum size 5 using an array.

Create a structure

struct queue {

int contents[5];

int front;

int count;

} ;

Note that the array contents holds the contents of the queue and the integer front stores the index of the front element in the queue.

Write a program to implement enQueue and deQueue operation on queue and to display the contents of the queue.

In the initQueue function intialize the value of front and count to 0.

Print the message “Queue is full” in the enQueue function when an attempt is made to insert a data into a full queue.

Print the message “Queue is empty” in the deQueue function and return the value -1000 when an attempt is made to delete data from an empty queue.

Refer function specifications for further details.

code:

	#include<stdio.h> #include<string.h>
	struct queue {
	int contents[5];
	int front;
	int count;
	} ;
	void initQueue(struct queue * q);
	void enQueue(struct queue * q, int element);
	int deQueue(struct queue * q);
	void display( struct queue q);
	void printMenu();
	int main()
	{
	struct queue p;
	int data,ch, data1;
	initQueue(&p);
	do {
	printMenu();
	printf("Enter your choice\n");
	scanf("%d",&ch);
	switch(ch) {
	case 1:
	printf("Enter the element to be inserted/entered\n");
	scanf("%d",&data);
	enQueue(&p, data);
	break;
	case 2:
	data1 = deQueue(&p);
	if(data1 != -1000)
	printf("The deleted element is %d\n",data1);
	break;
	case 3:
	printf("The contents of the queue are");
	display(p);
	printf("\n");
	break;
	default:
	return 0;
	}
	} while(1);
	return 0;
	}
	void printMenu()
	{
	printf("Choice 1 : Enter element into Queue\n");
	printf("Choice 2 : Delete element from Queue\n");
	printf("Choice 3 : Display\n");
	printf("Any other choice : Exit\n");
	}
	void initQueue(struct queue * q)
	{
	q->front=0;
	q->count=0;
	}
	void enQueue(struct queue * q, int element)
	{
	int index;
	index=(q->count+q->front)%5;
	if(index==q->front&&q->count!=0)
	printf("Queue is full\n");
	else
	{
	q->count++;
	q->contents[index]=element;
	}
	}
	int deQueue(struct queue * q)
	{
	int elem;
	if(q->count==0)
	{
	printf("Queue is empty\n");
	return (-1000);
	}
	elem=q->contents[q->front];
	q->count--;
	q->front=(q->front+1)%5;
	return elem;
	}
	void display( struct queue q)
	{
	int i,index;
	if(q.count==0)
	printf(" {}");
	else
	{
	for(index=q.front,i=1;i<=q.count;i++,index++)
	printf(" %d",q.contents[index%5]);
	}
	}