How should I use the qsort function?

Please tell me ho to use the qsort function. A listing would be nice.

This'll sort a array of 10 random int's -

Code:

---

#include <iostream>
#include <cstdlib>
#include <ctime>
using namespace std;

int compare(const void* first, const void* second)
{
        if (*(int*)first<*(int*)second)
                return -1;
       
        if (*(int*)first>*(int*)second)
                return 1;

        return 0;
}


int main()
{
        srand((unsigned)time(0));
        int array[10];

        for(int i=0;i<10;i++)
                array[i]=rand()%10000;

        qsort(array,sizeof(array)/sizeof(int),sizeof(int),compare);

        for(int j=0;j<10;j++)
                cout << array[j] << endl;


        return 0;
}

---

Thanks. That worked. Niw, another question. I have the following structure
struct book
{
char name[30];
char book[30];
}b[10];
How can I sort this array by the name of the book using the qsirt function?

You'll have to modify the compare function to call strcmp()- in <cstring> -

Code:

---

int compare(const void* first, const void* second)
{
        return strcmp(((book*)first)->books,((book*)second)->books);

}

---

assuming your struct has a books[30] member.