m01fsc searches a sorted vector of
arbitrary type data objects, which are stored in the elements of an array at intervals of length
stride.
vec must have previously been sorted into the specified order.
The function searches for the first or last match depending on the value of
final. It returns Nag_TRUE if an exact match is found and
match is set to point at that object. If there is no exact match then Nag_FALSE is returned and
match is set to point to either the next later element, if
, or the next earlier element, if
.
None.
-
1:
– Pointer
Input
-
On entry: the object to search for.
-
2:
– const Pointer
Input
-
On entry: the array of objects to be searched.
-
3:
– size_t
Input
-
On entry: the number of objects to be searched.
Constraint:
, where is an implementation-dependent value for the maximum size of an array.
-
4:
– ptrdiff_t
Input
-
On entry: the increment between data items in
vec to be searched.
Note: if
stride is positive,
vec should point at the first data object; otherwise
vec should point at the last data object.
Constraint:
, where
is an implementation-dependent value for the maximum size_t size on the system, divided by
n if
n is positive.
-
5:
– function, supplied by the user
External Function
-
m01fsc compares two data objects. If its arguments are pointers to a structure, this function must allow for the offset of the data field in the structure (if it is not the first).
The function must return:
|
if the first data field is less than the second, |
|
if the first data field is equal to the second, |
|
if the first data field is greater than the second. |
The specification of
compare is:
| Integer |
compare (const Nag_Pointer a,
const Nag_Pointer b)
|
|
-
1:
– const Nag_Pointer
Input
-
On entry: the first data field.
-
2:
– const Nag_Pointer
Input
-
On entry: the second data field.
-
6:
– Nag_SortOrder
Input
-
On entry: specifies whether the array will be sorted into ascending or descending order.
Constraint:
or .
-
7:
– Nag_SearchMatch
Input
-
On entry: specifies whether to search for the first or last match. This also determines the pointer returned if an exact match cannot be found.
Constraint:
or .
-
8:
– Pointer *
Output
-
On exit: if an exact match is found this is a pointer to a pointer to the matching data object. If an exact match is not found this is set to point to the nearest object. If this is the next later element, otherwise the next earlier element.
-
9:
– NagError *
Input/Output
-
The NAG error argument (see
Section 7 in the Introduction to the NAG Library CL Interface).
Not applicable.
The example program reads a key and a list of real numbers, which have been sorted into ascending order. It then searches the list for the first number which matches the key.