CODEWITHSUNDEEP
ccompiler-errorsbinary-search
Sam
Sam

Reputation: 461

binary search function finishing without returning int

I have looked through this function over and over and cannot figure out why I am getting this warning/error when trying to compile the code. The compiler I use runs with -Werror so I am not sure if it is a warning or an error, but the error I am getting is:

error: control may reach end of non-void function [-Werror,-Wreturn-type]

Here is my function

int binarySearch(int key, int array[], int min, int max)
{
    //Check if there is value is not found
    if(max < min)
    {
        return -1;
    }
    else
    {
        //find midpoint
        int midpoint = (min + max) / 2;

        //Run recursive steps
        if(array[midpoint] < key)
        {
            binarySearch(key, array, midpoint + 1, max);
        }
        else if(array[midpoint] > key)
        {
            binarySearch(key, array, min, midpoint - 1);
        }
        else
        {
            return midpoint;
        }
    }
}

Upvotes: 0

Views: 173

Answers (1)

Ray
Ray

Reputation: 1973

If array[midpoint] < key or array[midpoint] > key, you call binarySearch recursively and then fall off the end of the function without specifying a return value. You presumably want to return the value returned by the recursive calls in those two branches, e.g. 

return binarySearch(key, array, midpoint + 1, max);

(To answer your other question, the compiler diagnostic would have been a warning if -Werror wasn't set, but the warning indicates a bug in the code, which is of course why -Werror is generally a good idea.)

Upvotes: 2

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