Un-sorted list, find the "k" largest value, the original list can be changed

#include

int find_k_largest_number(int *arr, int size, int k)
{
int pivot = arr[0], i=0, j=size-1, m;

if (k > size) return -1;	// not found

#if 0
printf("before sort, size = %d, k = %d\n", size, k);
for(m=0; m= pivot)
{
j--;
}
else
{
break;
}
}

if (i != j)
{
arr[i] = arr[j];
i++;
}

while (i (k-1))
{
return find_k_largest_number(arr, i, k);
}
else
{
return find_k_largest_number(arr+i+1, size - i -1, k-i-1);
}
}

#define ARRAY_SIZE (10)

int main()
{
int a[ARRAY_SIZE] = {3,5,10,1,2,6,8,4,7,9};
int k_value;

printf("find-k-largest-number begin\n");

k_value = find_k_largest_number(a, ARRAY_SIZE, 9);
printf("%d-largest-number is %d\n", 9, k_value);

k_value = find_k_largest_number(a, ARRAY_SIZE, 1);
printf("%d-largest-number is %d\n", 1, k_value);

k_value = find_k_largest_number(a, ARRAY_SIZE, 2);
printf("%d-largest-number is %d\n", 2, k_value);

k_value = find_k_largest_number(a, ARRAY_SIZE, 3);
printf("%d-largest-number is %d\n", 3, k_value);

k_value = find_k_largest_number(a, ARRAY_SIZE, 20);
printf("%d-largest-number is %d\n", 20, k_value);

printf("find-k-largest-number end\n");

return 0;
}