* <<defs,Definitions>>
* <<examples,Examples>>
- - <<ex_numbers,Numbers>>
- - <<ex_strings,Strings>>
!!ucw/binsearch.h
for several different cases, for example to find lower elements in a (non-)decreasing array or even to find
elements in a (non-)increasing array.
-[[ex_num]]
-Numbers
-~~~~~~~
-
static int inc[10] = { 1, 4, 4, 5, 6, 10, 11, 20, 25, 50 };
+ static const char *str[5] = { "aaa", "abc", "bflmpsvz", "rep", "rep" };
static int dec[3] = { 5, 2, 1 };
// find the first equal element
printf("%d\n", BIN_SEARCH_GE(inc, 10, 4)); // prints 1
printf("%d\n", BIN_SEARCH_GE(inc, 10, 99)); // prints 10 (not found)
- // find the first greater element
+ // find the last equal element (or -1 if does not exist)
#define CMP_LE(ary, i, x) ((ary[i]) <= (x))
+ int i = BIN_SEARCH_FIRST_GE_CMP(inc, 10, 4, CMP_LE);
+ printf("%d\n", (i && inc[i - 1] == 4) ? i - 1 : -1); // prints 2
+
+ // find the first greater element
printf("%d\n", BIN_SEARCH_FIRST_GE_CMP(inc, 10, 25, CMP_LE)); // prints 9
- // find the last lower or equal element (or -1 if not found)
+ // find the last lower or equal element (or -1 if does not exist)
printf("%d\n", BIN_SEARCH_FIRST_GE_CMP(inc, 10, 25, CMP_LE) - 1); // prints 8
- // find the last lower element (or -1 if not found)
+ // find the last lower element (or -1 if does not exist)
printf("%d\n", BIN_SEARCH_FIRST_GE(inc, 10, 25) - 1); // prints 7
+ // find the first greater or equal string
+ #define CMP_STR(ary, i, x) (strcmp((ary[i]), (x)) < 0)
+ printf("%d\n", BIN_SEARCH_GE_CMP(str, 5, "bfl", CMP_STR)); // prints 2
+
// find the first lower or equal element in the non-increasing array
#define CMP_GT(ary, i, x) ((ary[i]) > (x))
printf("%d\n", BIN_SEARCH_FIRST_GE_CMP(dec, 3, 4, CMP_GT)); // prints 1
-
- // ...
-
-[[ex_str]]
-Strings
-~~~~~~~
-
- static char *str[5] = { "aaa", "abc", "bflmpsvz", "rep", "rep" };
-
- #define CMP_STR(ary, i, x) (strcmp((ary[i]), (x)) < 0)
-
- printf("%d\n", BIN_SEARCH_GE_CMP(str, 5, "bfl", CMP_STR)); // prints 2