bsearch

bsearch

二分法搜索

void*bsearch(const void *key, const void *base, size_t *nelem, size_t width, int(*fcmp)(const void *, const *));

#include

#include

#define NELEMS(arr) (sizeof(arr) / sizeof(arr【0】))

int numarray【】 = {123, 145, 512, 627, 800, 933};

int numeric (const int *p1, const int *p2)

{

return(*p1 - *p2);

}

int lookup(int key)

{

int *itemptr;

itemptr = bsearch (&key, numarray, NELEMS(numarray),

sizeof(int), (int(*)(const void *,const void *))numeric);

return (itemptr != NULL);

}

int main(void)

{

if (lookup(512))

printf("512 is in the table.\n");

else

printf("512 isn't in the table.\n");

return 0;

}