sorting array of objects...

[spl]

I have an array of objects. I want to sort the array of a
given numeric value that exists in each of the objects. Suppose the
array of objects is called student and the numeric value I want to
sort the array based on the member is called "rollno".
ex:
struct student{
int rollno;
int name;
int status;
};
student obj[10]
here, I have to sort obj of 10objects, based on rollno.

Please give your suggestion for any fast method?

[Pedro Graca]

Re: sorting array of objects...

spl wrote:
[...]

here, I have to sort obj of 10objects, based on rollno.
>
Please give your suggestion for any fast method?

http://en.wikipedia.org/wiki/Insertion_sort

[Malcolm McLean]

Re: sorting array of objects...


"spl" <splender.dev@g mail.comwrote in message
news:e2b7068f-1035-4e16-8ba6-14b0a421bad1@p2 5g2000hsf.googl egroups.com...

>I have an array of objects. I want to sort the array of a
given numeric value that exists in each of the objects. Suppose the
array of objects is called student and the numeric value I want to
sort the array based on the member is called "rollno".
ex:
struct student{
int rollno;
int name;
int status;
};
student obj[10]
here, I have to sort obj of 10objects, based on rollno.
>
Please give your suggestion for any fast method?

int compfunct(const void *e1, const void *e2)
{
const student *s1 = e1;
const student *s2 = e2;

return s1->rollno - s2->rollno;
}

in main body of code:

qsort(obj, 10, sizeof(student) , compfunct);

--
Free games and programming goodies.

http://www.personal.leeds.ac.uk/~bgy1mm

[Ben Bacarisse]

Re: sorting array of objects...

spl <splender.dev@g mail.comwrites:

I have an array of objects. I want to sort the array of a
given numeric value that exists in each of the objects. Suppose the
array of objects is called student and the numeric value I want to
sort the array based on the member is called "rollno".

You've been pointer to qsort and this is the right advice, but...

ex:
struct student{
int rollno;
int name;
int status;
};
student obj[10]

This looks like C++ not C. If youy are to use C++ (and I take it this
is homework) you might be expected to do it the C++ way. To find out
about this, post in comp.lang.c++.

[And why is the name an int?]

--
Ben.

[pete]

Re: sorting array of objects...

Malcolm McLean wrote:

>
"spl" <splender.dev@g mail.comwrote in message
news:e2b7068f-1035-4e16-8ba6-14b0a421bad1@p2 5g2000hsf.googl egroups.com...

I have an array of objects. I want to sort the array of a
given numeric value that exists in each of the objects. Suppose the
array of objects is called student and the numeric value I want to
sort the array based on the member is called "rollno".
ex:
struct student{
int rollno;
int name;
int status;
};
student obj[10]
here, I have to sort obj of 10objects, based on rollno.

Please give your suggestion for any fast method?

>
int compfunct(const void *e1, const void *e2)
{
const student *s1 = e1;
const student *s2 = e2;
>
return s1->rollno - s2->rollno;
}
>
in main body of code:
>
qsort(obj, 10, sizeof(student) , compfunct);

That's undefined if s1->rollno equals INT_MAX and s2->rollno equals -1,
and what you wrote
is also undefined for about a zillion other scenarios.

int compfunct(const void *e1, const void *e2)
{
const student *s1 = e1;
const student *s2 = e2;

return s2->rollno s1->rollno ? -1 : s2->rollno != s1->rollno;
}

--
pete