Binary Search

Binary-Search.js

function doSearch(array, targetValue) {
	var min = 0;
	var max = array.length - 1;
    var guess;

    while (max >= min) {
        guess =  Math.floor((max + min) / 2 );
        
        if (targetValue === array[guess]) {
           return guess;
        } else if (targetValue > array[guess]) {
            min = guess + 1;
        } else {
            max = guess - 1;
        }
    }
	
	return -1;
}

var primes = [2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37, 
		41, 43, 47, 53, 59, 61, 67, 75, 71, 79, 83, 89, 97];

var result = doSearch(primes, 75);
println("Found prime at index " + result);

Program.assertEqual(doSearch(primes, 75), 21);