二分查找 java递归和非递归实现

public static int rank(int []a , int x, int lo, int hi)
{
if(hi<lo)
return -1;
if(a[lo+(hi-lo)/2]>x)
return rank(a,x,lo,lo+(hi-lo)/2-1);
else if(a[lo+(hi-lo)/2]<x)
return rank(a,x,lo+(hi-lo)/2+1,hi);
else
return a[lo+(hi-lo)/2];
}

public static int rank(int[]a,int key)
{
int hi = a.length-1;
int lo = 0;
while(lo<=hi) {
int mid = lo+(hi-lo)/2;
if (key > a[mid]) lo = mid +1;
else if (key < a[mid]) hi = mid -1;
else return a[mid];
}
return -1;
}