Program to maintain a heap.

#include <"stdio.h">
#include <"conio.h">

void restoreup ( int, int * ) ;
void restoredown ( int, int *, int ) ;
void makeheap ( int *, int ) ;
void add ( int, int *, int * ) ;
int replace ( int, int *, int ) ;
int del ( int *, int * ) ;

void main( )
{
int arr [20] = { 1000, 7, 10, 25, 17, 23, 27, 16,
19, 37, 42, 4, 33, 1, 5, 11 } ;
int i, n = 15 ;

clrscr( ) ;
makeheap ( arr, n ) ;

printf ( "Heap:\n" ) ;
for ( i = 1 ; i <= n ; i++ )
printf ( "%d\t", arr [i] ) ;

i = 24 ;
add ( i, arr, &n ) ;

printf ( "\n\nElement added %d.\n", i ) ;
printf ( "\nHeap after addition of an element:\n" ) ;
for ( i = 1 ; i <= n ; i++ )
printf ( "%d\t", arr [i] ) ;

i = replace ( 2, arr, n ) ;
printf ( "\n\nElement replaced %d.\n", i ) ;
printf ( "\nHeap after replacement of an element:\n" ) ;
for ( i = 1 ; i <= n ; i++ )
printf ( "%d\t", arr [i] ) ;

i = del ( arr, &n ) ;
printf ( "\n\nElement deleted %d.\n", i ) ;
printf ( "\nHeap after deletion of an element:\n" ) ;
for ( i = 1 ; i <= n ; i++ )
printf ( "%d\t", arr [i] ) ;

getch( ) ;
}

void restoreup ( int i, int *arr )
{
int val ;
val = arr [i] ;
while ( arr [i / 2] <= val )
{
arr [i] = arr [i / 2] ;
i = i / 2 ;
}
arr [i] = val ;
}

void restoredown ( int pos, int *arr, int n )
{
int i, val ;
val = arr [pos] ;
while ( pos <= n / 2 )
{
i = 2 * pos ;
if ( ( i < n ) && ( arr [i] < arr [i + 1] ) )
i++ ;
if ( val >= arr [i] )
break ;
arr [pos] = arr [i] ;
pos = i ;
}
arr [pos] = val ;
}

void makeheap ( int *arr, int n )
{
int i ;
for ( i = n / 2 ; i >= 1 ; i-- )
restoredown ( i, arr, n ) ;
}

void add ( int val, int *arr, int *n )
{
( *n ) ++ ;
arr [*n] = val ;
restoreup ( *n, arr ) ;
}
int replace ( int i, int *arr, int n )
{
int r = arr [1] ;
arr [1] = i ;
for ( i = n / 2 ; i >= 1 ; i-- )
restoredown ( i, arr, n ) ;
return r ;
}

int del ( int *arr, int *n )
{
int val ;
val = arr [1] ;
arr [1] = arr [*n] ;
( *n ) -- ;
restoredown ( 1, arr, *n ) ;
return val ;
}