int binary_search_recursive(int *seq, int lbound, int ubound, int val) {
int i=(lbound+ubound)/2;
if(ubound<lbound)
return -1;
if(seq[i]==val)
return i;
else if(seq[i]>val)
return binary_search_recursive(seq, lbound, i-1, val);
return binary_search_recursive(seq, i+1, ubound, val);
}
// plain ol' binary search, this time recursive
int binary_search_recursive(int *array, int low, int high, int value)
{
int middle = (low + high) / 2;
if(low > high)
return -1;
if(array[middle] == value)
{
return middle;
}
else if(array[middle] < value)
{
return binary_search_recursive(array, middle+1, high, value);
}
else
{
return binary_search_recursive(array, low, middle-1, value);
}
}
// __expected:binary_search_recursive(imin => $_retval, imax => $_retval, key => $_retval, A => $_retval, A => A)
int binary_search_recursive(int A[], int key, int imin, int imax)
{
// test if array is empty
if (imax < imin)
// set is empty, so return value showing not found
return KEY_NOT_FOUND;
else
{
// calculate midpoint to cut set in half
int imid = midpoint(imin, imax);
// three-way comparison
if (A[imid] > key)
// key is in lower subset
return binary_search_recursive(A, key, imin, imid - 1);
else if (A[imid] < key)
// key is in upper subset
return binary_search_recursive(A, key, imid + 1, imax);
else
// key has been found
return imid;
}
}
int main()
{
int arr[] = { 5, 3, 2, 4, 1, 4, 3, 2, 6, 2, 7 };
int length = sizeof(arr) / sizeof(int);
print_array(arr, length);
bubble_sort(arr, length);
//selection_sort(arr, length);
//insertion_sort(arr, length);
print_array(arr, length);
printf("%d\n", binary_search(arr, length, 2));
printf("%d\n", binary_search_recursive(arr, 0, length, 2));
return 0;
}