bsearch2.c

自己做的常用库和实现的数据结构。public domain.

#include<stdio.h>
int cmp(const void *a, const void *b)
{
	return *((int *)b) - *((int *)a);	
}
void *bs(const void *key, const void *base, size_t nmemb, size_t size,
		int (*compar)(const void *, const void *))
{
	const void *low=base, *high=low+nmemb*size, *mid=low+(nmemb>>=1)*size;
	int t;
	while(high >= low) {
		t = (*compar)(key,mid);
		if(t==0)
			return (void *)mid;
		else if(t>0) 
			low = mid+size;
		else 
			high = mid-size;
		mid = low + size*(nmemb>>=1);
	}
	return NULL;
}
main()
{
	int a[10];
	int i;
	int *q;
	for(i=0;i<10; i++)
		printf("%d ",a[i]=-i);
	q = (int *)bs(a+4, a, 10, sizeof(int), cmp);
	printf("\nafterbsearch%d", *q);
}