How correctly sort an array?

Question

I have this code for sort array polsum:

int comp (const void * a, const void * b){   
   double aa = *(double*)a, bb = *(double*)b;

   if (aa < bb) return -1;
   if (aa > bb) return  1;
   return 0;
}

double sort(double *polsum){                              
    int p;
    qsort(polsum, sizeof(double),sizeof(double), comp);
    return 0;
}

But output is:

5,01/
80,86/
85,01/
85,01/
300,88/
600,88/
77888,88/
100400,00/
670,88/
80,86/
80,86/

Where have I made a mistake?

You're not showing us your full code.

000
– 000

2013-04-08 18:30:02 +00:00
Commented Apr 8, 2013 at 18:30 — 000
– 000, Commented Apr 8, 2013 at 18:30

jeremy · Accepted Answer · 2013-04-08 18:53:18Z

1

Your passing in sizeof(double) for the count of elements to be sorted. sizeof(double) == 8

Consider adding the following to your sort function:

double sort(double *polsum, int count) {
    int p;
    qsort(polsum, count, sizeof(double), comp);
    return 0;
}

edited Apr 8, 2013 at 18:53

answered Apr 8, 2013 at 18:33

jeremy

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2 Comments

Tomáš Čičman Over a year ago

but why? how can I repair this please? I really don't know

jeremy Over a year ago

Your passing in an array of doubles, you should, at some point know how many elements there are. You should pass in the number of elements to your sort function.

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