Dequeue using an array Implementation in Turbo C

#include <stdio.h>
#include <conio.h>
#define MAX 10
void addqatbeg ( int *, int, int *, int * ) ;
void addqatend ( int *, int, int *, int * ) ;
int delqatbeg ( int *, int *, int * ) ;
int delqatend ( int *, int *, int * ) ;
void display ( int * ) ;
int count ( int * ) ; 
void main( )
{
int arr[MAX] ;
int front, rear, i, n ;
clrscr( ) ;
/* initialises data members */
front = rear = -1 ;
for ( i = 0 ; i < MAX ; i++ )
arr[i] = 0 ;
addqatend ( arr, 17, &front, &rear ) ;
addqatbeg ( arr, 10, &front, &rear ) ;
addqatend ( arr, 8, &front, &rear ) ;
addqatbeg ( arr, -9, &front, &rear ) ;
addqatend ( arr, 13, &front, &rear ) ;
addqatbeg ( arr, 28, &front, &rear ) ;
addqatend ( arr, 14, &front, &rear ) ;
addqatbeg ( arr, 5, &front, &rear ) ;
addqatend ( arr, 25, &front, &rear ) ;
addqatbeg ( arr, 6, &front, &rear ) ;
addqatend ( arr, 21, &front, &rear ) ;
addqatbeg ( arr, 11, &front, &rear ) ;
printf ( "\nElements in a deque: " ) ;
display ( arr ) ;
n = count ( arr ) ;
printf ( "\nTotal number of elements in deque: %d", n ) ;
i = delqatbeg ( arr, &front, &rear ) ;
printf ( "\nItem extracted: %d", i ) ;
i = delqatbeg ( arr, &front, &rear ) ;
printf ( "\nItem extracted:%d", i ) ;
i = delqatbeg ( arr, &front, &rear ) ;
printf ( "\nItem extracted:%d", i ) ;
i = delqatbeg ( arr, &front, &rear ) ;
printf ( "\nItem extracted: %d", i ) ;
printf ( "\nElements in a deque after deletion: " ) ;
display ( arr ) ;
addqatend ( arr, 16, &front, &rear ) ;
addqatend ( arr, 7, &front, &rear ) ; 
printf ( "\nElements in a deque after addition: " ) ;
display ( arr ) ;
i = delqatend ( arr, &front, &rear ) ;
printf ( "\nItem extracted: %d", i ) ;
i = delqatend ( arr, &front, &rear ) ;
printf ( "\nItem extracted: %d", i ) ;
printf ( "\nElements in a deque after deletion: " ) ;
display ( arr ) ;
n = count ( arr ) ;
printf ( "\nTotal number of elements in deque: %d", n ) ;
getch( ) ;
}
/* adds an element at the beginning of a deque */
void addqatbeg ( int *arr, int item, int *pfront, int *prear )
{
int i, k, c ;
if ( *pfront == 0 && *prear == MAX - 1 )
{
printf ( "\nDeque is full.\n" ) ;
return ;
}
if ( *pfront == -1 )
{
*pfront = *prear = 0 ;
arr[*pfront] = item ;
return ;
}
if ( *prear != MAX - 1 )
{
c = count ( arr ) ;
k = *prear + 1 ;
for ( i = 1 ; i <= c ; i++ )
{
arr[k] = arr[k - 1] ;
k-- ;
}
arr[k] = item ;
*pfront = k ;
( *prear )++ ;
}
else
{
( *pfront )-- ;
arr[*pfront] = item ;
}
}
/* adds an element at the end of a deque */
void addqatend ( int *arr, int item, int *pfront, int *prear )
{
int i, k ;
if ( *pfront == 0 && *prear == MAX - 1 )
{
printf ( "\nDeque is full.\n" ) ;
return ;
}
if ( *pfront == -1 )
{
*prear = *pfront = 0 ;
arr[*prear] = item ;
return ;
} 
if ( *prear == MAX - 1 )
{
k = *pfront - 1 ;
for ( i = *pfront - 1 ; i < *prear ; i++ )
{
k = i ;
if ( k == MAX - 1 )
arr[k] = 0 ;
else
arr[k] = arr[i + 1] ;
}
( *prear )-- ;
( *pfront )-- ;
}
( *prear )++ ;
arr[*prear] = item ;
}
/* removes an element from the *pfront end of deque */
int delqatbeg ( int *arr, int *pfront, int *prear )
{
int item ;
if ( *pfront == -1 )
{
printf ( "\nDeque is empty.\n" ) ;
return 0 ;
}
item = arr[*pfront] ;
arr[*pfront] = 0 ;
if ( *pfront == *prear )
*pfront = *prear = -1 ;
else
( *pfront )++ ;
return item ;
}
/* removes an element from the *prear end of the deque */
int delqatend ( int *arr, int *pfront, int *prear )
{
int item ;
if ( *pfront == -1 )
{
printf ( "\nDeque is empty.\n" ) ;
return 0 ;
}
item = arr[*prear] ;
arr[*prear] = 0 ;
( *prear )-- ;
if ( *prear == -1 )
*pfront = -1 ;
return item ;
}
/* displays elements of a deque */
void display ( int *arr )
{
int i ;
printf ( "\n front->" ) ;
for ( i = 0 ; i < MAX ; i++ )
printf ( "\t%d", arr[i] ) ;
printf ( " <-rear" ) ;
}
/* counts the total number of elements in deque */
int count ( int *arr )
{
int c = 0, i ;
for ( i = 0 ; i < MAX ; i++ )
{
if ( arr[i] != 0 )
c++ ;
}
return c ;
}

Circular queue as an array Implementation in Turbo C

#include <stdio.h>
#include <conio.h>
#define MAX 10
void addq ( int *, int, int *, int * ) ;
int delq ( int *, int *, int * ) ;
void display ( int * ) ;
void main( )
{
int arr[MAX] ;
int i, front, rear ;
clrscr( ) ;
/* initialise data member */
front = rear = -1 ;
for ( i = 0 ; i < MAX ; i++ )
arr[i] = 0 ;
addq ( arr, 14, &front, &rear ) ;
addq ( arr, 22, &front, &rear ) ;
addq ( arr, 13, &front, &rear ) ;
addq ( arr, -6, &front, &rear ) ;
addq ( arr, 25, &front, &rear ) ;
printf ( "\nElements in the circular queue: " ) ;
display ( arr ) ;
i = delq ( arr, &front, &rear ) ;
printf ( "Item deleted: %d", i ) ;
i = delq ( arr, &front, &rear ) ;
printf ( "\nItem deleted: %d", i ) ;
printf ( "\nElements in the circular queue after deletion: " ) ;
display ( arr ) ;
addq ( arr, 21, &front, &rear ) ;
addq ( arr, 17, &front, &rear ) ;
addq ( arr, 18, &front, &rear ) ;
addq ( arr, 9, &front, &rear ) ;
addq ( arr, 20, &front, &rear ) ;
printf ( "Elements in the circular queue after addition: " ) ;
display ( arr ) ;
addq ( arr, 32, &front, &rear ) ;
printf ( "Elements in the circular queue after addition: " ) ;
display ( arr ) ;
getch( ) ;
}
/* adds an element to the queue */
void addq ( int *arr, int item, int *pfront, int *prear )
{
if ( ( *prear == MAX - 1 && *pfront == 0 ) || ( *prear + 1 == *pfront ) )
{
printf ( "\nQueue is full." ) ;
return ;
}
if ( *prear == MAX - 1 )
*prear = 0 ;
else
( *prear )++ ;
arr[*prear] = item ;
if ( *pfront == -1 )
*pfront = 0 ;
}
/* removes an element from the queue */
int delq ( int *arr, int *pfront, int *prear )
{
int data ;
if ( *pfront == -1 )
{
printf ( "\nQueue is empty." ) ;
return NULL ;
}
data = arr[*pfront] ;
arr[*pfront] = 0 ;
if ( *pfront == *prear )
{
*pfront = -1 ;
*prear = -1 ;
}
else
{
if ( *pfront == MAX - 1 )
*pfront = 0 ;
else
( *pfront )++ ;
}
return data ;
}
/* displays element in a queue */
void display ( int * arr )
{
int i ;
printf ( "\n" ) ;
for ( i = 0 ; i < MAX ; i++ )
printf ( "%d\t", arr[i] ) ;
printf ( "\n" ) ;
}