return value

[messages]

This recursive function doesnt have a end point,becuase 12 item is not exist in the array.How we can fix this recursive function to solve this problem?

int _tmain(int argc, _TCHAR* argv[])
{
int arr[10] = {1,2,3,4,5,6,7,8,9,10};
int sum;

  sum=BinSearch(arr,12,0,9);
	  cout< A\[mid\])
		return Binary\_Search(A,item,mid+1,height);
	else
		return Binary\_Search(A,item,low,mid-1);

}

[Joe794]

1st line should be: if(low == height)return -1; // Return "Not Found"

[Joe794]

Add as 1st line in BinSearch: if(low > height)return -1; // Return 'not found' code

[messages]

Thank you Joe794.

[Aescleal]

The array passed into the function could potentially have any value in it you can't select a simple return value to represent your error condition. I'd consider throwing an exception rather than using a return value:

if( A[low] > item || A[high] < item] ) throw binary_search_out_of_bounds();

Another option is to have the function return a std::pair<bool, int> where the first item in the pair tells the caller if they have an error condition or not and the second is the value they're after. Personally I find that a bit ugly and it complicates your code more as you have to do more in the calling function so I'd go with an exception. Cheers, Ash

[messages]

Thank you Aescleal.