Here is the code:
public int Search(int[] nums, int target) {
return search(nums,target,0,nums.Length-1);
}
public int search(int[] n,int t,int s,int e)
{
if(s>e)
{
return -1;
}
int mid = (s+e)/2;
if(n[mid]==t)
{
return mid;
}
else if(t<n[mid])
{
return search(n,t,s,mid-1);
}
else
{
return search(n,t,mid+1,e);
}
}