public class BinSearch {

	public int binSearch(int k, int[]A, int lo, int hi){
	    // pre: A sorted
	    // post: if k in A[lo..hi] return its position; else return -1 
		 int ret;  // return value
		 if (lo>hi)  //Not found
			ret = -1;
	     else {
	     // invariant: if k in A[lo..hi] then  A[lo] <= k <= A[hi] 
		 int mid = (lo+hi)/2;

		 if (k==A[mid]) 
			ret = mid;
		 else if (k < A[mid])
			ret = binSearch(k,A,lo,mid-1); 
		 else  
			ret = binSearch(k,A,mid+1,hi); 
	     }
	     return ret;
	}

	
	
	
  public static void main(String[] args) {
	// TODO create array and binary search it
    BinSearch search = new BinSearch();
		
//  Initialize and print the sorted array
    int[] A = {0,2,4,6,8,10};
    System.out.print("A: ");
    for(int i=0; i<A.length;  i++)
    	System.out.print(A[i]+" ");
    System.out.println();
    
    int k;  // key we search or in A 
    for(k = 0; k<11; k++){
       int p; //position
       
       System.out.print("Binary Search: ");
       p = search.binSearch(k,A,0,A.length-1);
       System.out.println("pos of " + k + " in A: " + p);
    }
  }
}