How do I fix implicit conversion errors in my c# quicksort algorithm?

Question

I'm trying to implement a quicksort algorithm to sort an array of floats. Whenever I reference an index in the array, i get this error:

Cannot implicitly convert type 'float' to 'int'. An explicit conversion exists (are you missing a cast)?

Here's the algorithm:

class Quicksort
{
    public static void Sort(float[] numbers, int left, int right)
    {
        float i = Convert.ToSingle(left);
        float j = Convert.ToSingle(right);

        var pivot = numbers[(left + right) / 2];

        while (i <= j)
        {
            while (numbers[i] < pivot) //ERROR HERE
                i++;

            while (numbers[j] > pivot) //ERROR HERE
                j--;

            if (i <= j)
            {
                float tmp = numbers[i]; //ERROR HERE
                numbers[i] = numbers[j]; //ERROR HERE
                numbers[j] = tmp; //ERROR HERE

                i++;
                j--;
            }
        }

        if (left < j)
            Sort(numbers, left, j);

        if (i < right)
            Sort(numbers, i, right);
    }
}

The conversion error appears whenever i use numbers[i] or numbers[j]

How would I fix this?

Thanks

Answer 1

The problem is that you're trying to use floating point values for array indexes. That doesn't work: array indexes are always integers in C#, regardless of the type of the array element. That makes sense - there's no such thing as "element 1.3 of an array" for example.

Just change the first two lines of your method to:

int i = left;
int j = right;

... or remove i and j entirely, and use left and right throughout the method.