半分法查找

#include <stdio.h>
#include <stdlib.h>
int *binsearch(int *base, int len, int data);

int main()
{    
    int * p = NULL;
    int a[4] = {1, 2, 45, 68};//排好序的数组
    int data = 43;
    p = binsearch(a, 4, data);
    printf("%p
", p);
    system("pause");
    return 0;
}

int *binsearch(int *base, int len, int data)
{
   int *low = base, *high = base + len;
   int *mid = NULL;
   
   while(low < high)
   {
      mid = low + ((high - low) >> 1);
      if(data < *mid)
      {
          high = mid;
      }
      else if(data > *mid)
      {
          low = mid + 1;//mid + 1 不是 mid
      }
      else
      {
          return mid;
      }
   }

   return NULL;
}