Java binary search recursive

Question

I have to implement Binary search method which finds if value is or isn't in array. I have to use recurse.

public static boolean searchBin(int[] array, int x, int l, int r) {

        int center;

        center =(l+r) / 2;
        if ( x > array[center] )
        {
            l = center+1;
        }   
        else 
        {
            r = center-1;
        }

        if ( array[center] == x )
        {
            return true;
        }
        else
        {
            if ( l<=r )
            {
                searchBin(array,x,l,r); 
            }
            else
            {
                return false;
            }
        }
    }

I'm getting the following error:

Missing return statement

Thanks.

Because there exists a path on which you don't return anything. But the method should return something.. — Maroun
– Maroun, Commented Feb 27, 2014 at 20:36

Orel Eraki · Accepted Answer · 2014-02-27 20:37:26Z

2

This is because as the error suggests "not all paths return a value".

This is the possible problem:

searchBin(array,x,l,r);

A fix will be:

return searchBin(array,x,l,r);

answered Feb 27, 2014 at 20:37

Orel Eraki

12.2k4 gold badges31 silver badges38 bronze badges

Sign up to request clarification or add additional context in comments.

Comments

Joffrey · Accepted Answer · 2014-03-24 10:49:27Z

2

This is because one of the possible path of execution could lead to none of your return statements: in the last if, if the condition l<=r is true, nothing is returned (you only call recursively your method).

You might want to add the return keyword before your recursive call:

return searchBin(array,x,l,r);

This way, your method will (in this case) return whatever the recursive call returns.

edited Mar 24, 2014 at 10:49

answered Feb 27, 2014 at 20:36

Joffrey

38.3k8 gold badges90 silver badges118 bronze badges

Comments

Richard Miskin · Accepted Answer · 2014-02-27 20:38:18Z

1

There is no return where you have the recursive call to

searchBin

answered Feb 27, 2014 at 20:38

Richard Miskin

1,2607 silver badges12 bronze badges

Collectives™ on Stack Overflow

Java binary search recursive

3 Answers 3

Comments

Comments

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

3 Answers 3

Comments

Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Related