QUEUE

circularqueue.c

#include <stdio.h>
#include <stdlib.h>
#define MAX_SIZE 3
struct{
    int front;
    int rear;
    int a[MAX_SIZE];
    int size;
} typedef Queue;
void insert(Queue*, int);
int delete(Queue*);
int is_empty(Queue*);
int is_full(Queue*);
void display(Queue*);
int circ(int a){
    return a%MAX_SIZE;
}
void init(Queue*);

//end of header

void init(Queue* q)
{
    q->front = 0;
    q->rear = -1;
    q->size = 0;
}
void insert(Queue* q, int item)
{
    q->size++;
    q->rear = circ(++q->rear);
    q->a[q->rear] = item;
}
int delete(Queue* q)
{
    q->size--;
    int item;
    item = q->a[q->front++];
    q->front = circ(q->front);
    return item;
}
void display(Queue* q)
{
    int i;
    if(is_empty(q))
    {
        puts("Queue is empty");
    }
    else
    {
        puts("Elements in the queue");
        for(i=0;i<q->size;i++)
            printf("%d ",q->a[circ(q->front+i)]);
        puts("");
    }
}

int is_empty(Queue* q)
{
    return q->size <=0;
}
int is_full(Queue* q)
{
    return q->size >= MAX_SIZE;
}

int main()
{
    int ex=0, choice, item;
    Queue q;
    init(&q);
    while(!ex)
    {
        puts("Enter your choice\n1 Insertion\n2 Deletion\n3 Display\n4 Exit");
        scanf("%d",&choice);
        switch(choice)
        {
            case 1:
                if(is_full(&q))
                {
                    puts("Queue is full");
                }
                else
                {
                    puts("Enter the element");
                    scanf("%d", &item);
                    insert(&q,item);
                }
                break;
            case 2:
                if(is_empty(&q))
                {
                    puts("Queue is empty");
                }
                else
                {
                    printf("Deleted element %d \n", delete(&q));
                }
                break;
                
            case 3:
                display(&q);
                break;
                
            default:
                ex=1;
        }
    }
    return 0;
}

priorityqueue.c

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

struct
{
    int front;
    int rear;
    int a[MAX_SIZE];
} typedef Queue;

void init(Queue*);//initializes the queue

int delete(Queue*, int);//deletes element from queue

void display(Queue*);//displays queue

void insert(Queue*, int);//inserts an element into queue

int is_full(Queue*);//queue is full or not

int is_empty(Queue*);//queue is empty or not

//end of header
/**
 * @function init
 * @param q(Queue*)
 * Initialises the queue
 */
void init(Queue* q)
{
    q->front = 0;
    q->rear  =-1;
}
/**
 * @function delete
 * @param q(Queue*)
 * @param item(int)
 * @returns (int) Deletion was sucessfull or not
 * 
 */
int delete(Queue* q, int item)
{
    int i=q->front,j;
    while(q->a[i]!=item && (i<=q->rear))
        i++;
    if(i==(q->rear+1))
        return 0;
    for(j=i;j<=q->rear;j++)
    {
        q->a[j]=q->a[j+1];
    }
    q->rear--;
    return 1;
}
void insert(Queue* q, int item)
{
    int j=q->rear;
    while((j >= q->front)&&(item>q->a[j]))
    {
        q->a[j+1]= q->a[j];
        j--;
    }
    q->a[j+1] = item;
    q->rear++;
}
int is_empty(Queue* q)
{
    return q->front > q->rear;
}
int is_full(Queue* q)
{
    return q->rear >= (MAX_SIZE-1);
}
void display(Queue* q)
{
    int i;
    if(is_empty(q))
    {
        puts("Queue is empty");
    }
    else
    {
        for(i=q->front;i<= q->rear;i++)
            printf("%d ", q->a[i]);
        puts("");
    }
}

int main()
{
    int choice, ex=0, item;
    Queue q;
    init(&q);
    puts("1 Insert\n2 Delete\n3 Display\n4 Exit");
    while(!ex)
    {
        puts("Enter your choice");
        scanf("%d",&choice);
        switch(choice)
        {
            case 1:
                puts("Enter value");
                    scanf("%d", &item);
                if(is_full(&q))
                {
                    puts("Queue overflow");
                }
                else
                {
                    insert(&q,item);
                }
                break;
                
            case 2:
                if(is_empty(&q))
                {
                    puts("There are no elements to delete");
                }
                else
                {
                    puts("Enter value to delete");
                    scanf("%d", &item);
                    if(!delete(&q,item))
                        printf("%d not found\n", item);
                }
                break;
            case 3:
                display(&q);
                break;
            default:
                ex=1;
        }
   }
   return 0;
}

queue.c

#include <stdio.h>
#include <stdlib.h>

#define MAX_SIZE 5

struct{
    int front;
    int rear;
    int a[MAX_SIZE];
}typedef Queue;


void insert(Queue*,int);
int delete(Queue*);
void display(Queue*);
void initialize_Queue(Queue*);
int is_full(Queue*);
int is_empty(Queue*);
//end of header


int main()
{
    int choice,item,ex=0;
    Queue q;
    initialize_Queue(&q);
    while(!ex)
    {
        puts("Enter your choice\n1 Insertion\n2 Deletion\n3 Display\n4 Exit");
        scanf("%d",&choice);
        switch(choice)
        {
            case 1:
                if(is_full(&q))
                {
                    puts("Queue is full");
                } 
                else 
                {
                    puts("Enter the element to be inserted");
                    scanf("%d",&item);
                    insert(&q,item);
                }
                break;
                
            case 2:
                if(is_empty(&q))
                {
                    puts("Queue is empty");
                }
                else
                {
                    printf("%d deleted\n",delete(&q));
                }
                break;
                
            case 3:
                display(&q);
                break;
                
            default:
                ex = 1;
        }
    }
    return 0;
}

void initialize_Queue(Queue* q)
{
    q->rear = -1;
    q->front = 0;
}
int is_full(Queue* q)
{
    return q->rear == (MAX_SIZE -1);
}
int is_empty(Queue* q)
{
    return q->front > q->rear ;
}
void insert(Queue* q, int item)
{
    q->a[++q->rear] = item;
}
int delete(Queue*q)
{
    return q->a[q->front++];
}
void display(Queue* q)
{
    int i;
    if(is_empty(q))
    {
        puts("Queue is empty");
    }
    else
    {
        puts("Elements in the queue are");
        for(i=q->front;i<=q->rear;i++)   
            printf("%d ",q->a[i]);
        puts("");
    }
}