Queue_implementation.cpp

#include <stdio.h>
#include <stdlib.h>
typedef struct _queue_t
{
int *arr;
int rear, front, count, max;
} queue_t;
queue_t *queue_allocate (int n);
void queue_insert (queue_t * q, int v);
int queue_remove (queue_t * q);
int queue_count (queue_t * q);
int queue_is_empty (queue_t * q);
void stack_push (queue_t * q, int v)
{
queue_insert (q, v);
}
int stack_pop (queue_t * q)
{
int i, n = queue_count (q);
int removed_element;
for (i = 0; i < (n - 1); i++)
{
removed_element = queue_remove (q);
queue_insert (q, removed_element);
}
removed_element = queue_remove (q);
return removed_element;
}
int stack_is_empty (queue_t * q)
{
return queue_is_empty (q);
}
int stack_count (queue_t * q)
{
return queue_count (q);
}
int queue_count (queue_t * q)
{
return q->count;
}
queue_t *
queue_allocate (int n)
{
queue_t *queue;
queue = malloc (sizeof (queue_t));
if (queue == NULL)
return NULL;
queue->max = n;
queue->arr = malloc (sizeof (int) * n);
queue->rear = n - 1;
queue->front = n - 1;
return queue;
}
void
queue_insert (queue_t * q, int v)
{
if (q->count == q->max)
return 0;
q->rear = (q->rear + 1) % q->max;
q->arr[q->rear] = v;
q->count++;
}
int
queue_remove (queue_t * q)
{
int retval;
if (q->count == 0)
return;
q->front = (q->front + 1) % q->max;
retval = q->arr[q->front];
q->count--;
return retval;
}
int
queue_is_empty (queue_t * q)
{
return (q->count == 0);
}
void
queue_display (queue_t * q)
{
int i = (q->front + 1) % q->max, elements = queue_count (q);
while (elements--)
{
printf ("[%d], ", q->arr[i]);
i = (i >= q->max) ? 0 : (i + 1);
}
}
#define MAX 10
int
main (void)
{
queue_t *q;
int x, select;
q = queue_allocate (MAX);
do
{
printf ("\n[1] Push\n[2] Pop\n[0] Exit");
printf ("\nChoice: ");
scanf (" %d", &select);
switch (select)
{
case 1:
printf ("\nEnter value to Push:");
scanf (" %d", &x);
stack_push (q, x);
printf ("\nCurrent Queue:\n");
queue_display (q);
printf ("\n\nPushed Value: %d", x);
printf ("\n__________________________\n");
break;
case 2:
x = stack_pop (q);
printf ("\n\n\nCurrent Queue:\n");
queue_display (q);
if (x == -1)
printf ("\n\nNo values removed");
else
printf ("\n\nPopped Value: %d", x);
printf ("\n__________________________\n");
break;
case 0:
printf ("\nQutting.\n");
return 0;
default:
printf ("\nQutting.\n");
return 0;
}
}
while (1);
return 0;
}