Learn Recursion

Todays message is short and sweet.

I was just reading chapter seven of Beautiful Code, "Beautiful Testing". As the chapter begins, the reader is challenged to attempt writing a binary search. Here's mine.

int search(int[] arr, int target) {
    return arr.length == 0 ? -1 : search(arr, target, 0, arr.length-1);
}

int search(int[] arr, int target, int min, int max) {
    if (min >= max) return target == arr[min] ? min : -1;
    int middle =  (max + min) >>> 1;
    if (arr[middle] > target) return search(arr, target, min, middle-1);
    if (arr[middle] < target) return search(arr, target, middle+1, max);
    return middle;
}

Yes, it's in Java. I'm not going to rewrite it in eight other languages because that's not the point, for once.

Here's the point: If you call yourself a programmer and don't grok this recursion business, fix it. Now.

This has been a public service announcement brought to you by the "People Who Will Not Take You Seriously If You Don't Understand Recursion" Foundation.