Quick Sort

#include<stdio.h>
#include<limits.h>

void quick_sort(int, int);

int arr[100];

int main(void)
{
    arr[0] = INT_MIN;
    int n, i;
    printf("How many numbers : ");
    scanf("%d", &n);
    for(i=1; i<=n; i++)
    {
        arr[i] = rand()%1000;
    }

    printf("\n\nUnsorted Data :\n");
    for(i=1; i<=n; i++)
    {
        printf("%d ", arr[i]);
    }

    quick_sort(1, n);

    printf("\n\nSorted Data :\n");
    for(i=1; i<=n; i++)
    {
        printf("%d ", arr[i]);
    }
    return 0;
}

void quick_sort(int f, int l)
{
    int pivot, i, j, temp;

    if(f<l)
    {
        pivot = f;
        i =  f;
        j = l;

        while (i<j)
        {
            while (arr[i]<=arr[pivot])
            {
                i++;
            }
            while (arr[j]>arr[pivot])
            {
                j--;
            }
            if (i<j)
            {
                temp = arr[i];
                arr[i] = arr[j];
                arr[j] = temp;
            }
        }

        temp = arr[pivot];
        arr[pivot] = arr[j];
        arr[j] = temp;

        quick_sort(f, j-1);
        quick_sort(j+1, l);
    }
}