Heap

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From: sophia on 14 Apr 2008 08:55

---

Dear all,

what are the corrections/improvements needed in the following program
which shows the creation of heap from an array of elements ?


#include<stdio.h>
#include<stdlib.h>
#define MAX 50

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

int main(void)
{

int a[MAX] = {1000,7,10,25,17,23};
int n = 5,i;

makeheap(a,n);
display(a,n);

printf("\n\nEnter the element you want to add:: ");
i= readval();
add(i,a,&n);


printf("\nAfter adding the element %d\n",i);
display(a,n);

i = del(a,&n);
printf("\n\nAfter Deletion\n");
display(a,n);

puts("");
return EXIT_SUCCESS;
}


void makeheap(int *a,int n)
{
int i;

for(i= (n/2);i>= 1;i--)
restoredown(i,a,n);
}


void restoredown(int pos,int *a,int n)
{
int i,val;
val = a[pos];

while(pos <= n/2)
{
i = 2 * pos;

if((i < n) && (a[i] < a[i+1]))
i++;

if(val >= a[i])
break;

a[pos] = a[i];
pos = i;
}

a[pos] = val;
}


int readval()
{
int i,ch;

while( (1 != scanf("%d",&i)) )
{
while( (ch= fgetc(stdin)) != EOF && ch != '\n');
printf("\nSorry i could n't read that\nplease re enter the
value:: ");

if(1 == scanf("%d",&i))
break;
}

return i;
}


void display(int *a,int n)
{
int i;

printf("\n**********");
printf("\n HEAP ");
printf("\n**********\n");

puts("");
for(i=1;i <= n;i++)
printf("%d\t",a[i]);

}



void add(int val,int* a,int* n)
{
(*n)++;
a[*n] = val;
restoreup(*n,a);
}


void restoreup(int i,int *a)
{

int val;
val = a[i];

while(a[i/2] <= val)
{
a[i] = a[i/2];
i = i/2;
}

a[i] = val;
}


int del(int* a , int *n)
{
int temp,i;

temp = a[1];
a[1] = a[*n];
(*n)--;

restoredown(1,a,*n);
return temp;
}

From: Richard Heathfield on 14 Apr 2008 09:46

---

sophia said:

> Dear all,
>
> what are the corrections/improvements needed in the following program
> which shows the creation of heap from an array of elements ?

What are your thoughts on this? What have you tried? What are you stuck on?

<snip>

--
Richard Heathfield <http://www.cpax.org.uk>
Email: -http://www. +rjh@
Google users: <http://www.cpax.org.uk/prg/writings/googly.php>
"Usenet is a strange place" - dmr 29 July 1999

From: sophia on 14 Apr 2008 10:17

---

On Apr 14, 6:46 pm, Richard Heathfield <r...(a)see.sig.invalid> wrote:
> sophia said:
>
> > Dear all,
>
> > what are the corrections/improvements needed in the following program
> > which shows the creation of heap from  an array of elements ?
>
> What are your thoughts on this? What have you tried? What are you stuck on?

i am not getting you ,
what you mean by "what are you stuck on?"

From: Richard Heathfield on 14 Apr 2008 10:27

---

sophia said:

> On Apr 14, 6:46 pm, Richard Heathfield <r...(a)see.sig.invalid> wrote:
>> sophia said:
>>
>> > Dear all,
>>
>> > what are the corrections/improvements needed in the following program
>> > which shows the creation of heap from an array of elements ?
>>
>> What are your thoughts on this? What have you tried? What are you stuck
>> on?
>
> i am not getting you ,
> what you mean by "what are you stuck on?"

Which aspect of the problem you stated are you having difficulty in
solving?

--
Richard Heathfield <http://www.cpax.org.uk>
Email: -http://www. +rjh@
Google users: <http://www.cpax.org.uk/prg/writings/googly.php>
"Usenet is a strange place" - dmr 29 July 1999

From: sophia on 14 Apr 2008 13:40

---

On Apr 14, 10:27 am, Richard Heathfield <r...(a)see.sig.invalid> wrote:
> sophia said:
>
> > On Apr 14, 6:46 pm, Richard Heathfield <r...(a)see.sig.invalid> wrote:
> >> sophia said:
>
> >> > Dear all,
>
> >> > what are the corrections/improvements needed in the following program
> >> > which shows the creation of heap from an array of elements ?
>
> >> What are your thoughts on this? What have you tried? What are you stuck
> >> on?
>
> > i am not getting you ,
> > what you mean by "what are you stuck on?"
>
> Which aspect of the problem you stated are you having difficulty in
> solving?

well i have posted here, because i can get feedback from C gurus like
you,so that i can improve mu programming skills.

I would like to know if there is any other simpler/good method for
creating heap from an array of elements

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