二分查找

对一个已经排好序的整形数组进行二分查找，找到返回该数指针，否则返回NULL

 

#include <stdio.h>
#define NUM 20
#define XNUM 15
int * bsearch( int *t,int n,int x){
 int *lo = t;
 int *hi = t + n;
 while(lo < hi){
  int *mid = lo + ((hi-lo)>>1);
  if(x > *mid )
   lo = mid+1;
  else
   if(x < *mid )
    hi = mid;
   else
    return mid;
 }
 return NULL;
}

int main(){
 int t[NUM]={1,2,3,4,5,6,7,8,9,11,13,15,17,19,23,25};
 int reslut = 0;
 reslut = * bsearch(t,NUM,XNUM);

 printf("%d/n",reslut);
 return 1;
}