02_binary_search.js

const array = [0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15];
let count = 0;


function binarySearch(array, item) {
    let start = 0;
    let end = array.length;
    let middle;
    let found = false;
    let position = -1;

    while(!found && start <= end) {
        count++;
        middle = Math.floor((start + end) / 2);
        if (array[middle] === item) {
            found = true;
            position = middle;
            return position;
        }

        if (item < array[middle]) {
            end = middle - 1;
        } else {
            start = middle + 1;
        }
    }

    return position;
}

function recursiveBinarySearch(array, item, start, end) {
    const middle = Math.floor((start + end) / 2);
    count++;

    if (array[middle] === item) {
        return middle;
    }

    if (item < array[middle]) {
        return recursiveBinarySearch(array, item, start, middle - 1);
    } else {
        return recursiveBinarySearch(array, item, middle + 1, end);
    }
}

// console.log(binarySearch(array, 0));
console.log(recursiveBinarySearch(array, 11, 0, array.length));
console.log('count =', count);