Sorted Array to Balanced BST

PROBLEM :

Given a sorted array. Write a program that creates a Balanced Binary Search Tree using array elements. If there are n elements in array, then floor(n/2)'th element should be chosen as root and same should be followed recursively.

Input:

The first line of input contains an integer T denoting the number of test cases.
The first line of each test case is N,N is the size of array.
The second line of each test case contains N input A[].

Output:

Print the preorder traversal of constructed BST.

Constraints:

1 = T = 100
1 = N = 1000
1 = A[] = 10000

Example:

Input:
1
7
7 6 5 4 3 2 1

Output:
4 6 7 5 2 3 1


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SIMPLE c++ IMPLEMENTATION :
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#include<iostream>
using namespace std;
void preorder_tree(int [],int ,int ) ;
int main()
 {
int t,no,a[1000],i ;
cin>>t ;
while(t--)
{
   cin>>no ;
   for(i=0;i<no;i++)
   cin>>a[i] ;
 
   preorder_tree(a,0,no-1) ;
   cout<<endl ;
}
return 0;
}

void preorder_tree(int a[],int start,int end)
{
    if(start>end)
        return ;
    if(start==end)
    {
        cout<<a[start]<<" " ;
        return ;
    }
    int no=(start+end)/2 ;
    cout<<a[no]<<" " ;
    preorder_tree(a,start,no-1) ;
    preorder_tree(a,no+1,end) ;
}

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