Merge pull request #9 from smokyabdulrahman/js-binary-search

JavaScript binary search - Issue #4

search/binary_search/JavaScript/binary_search.js

@@ -0,0 +1,33 @@
+// takes sorted array and key
+// returns index of key elemnt, -Infinity otherwise
+function binarySearch(array, key) {
+    first = 0;
+    last = array.length;
+    middle = (first + last) / 2;
+    while (first <= last) {
+        // the middle value is smaller than wanted key
+        // search upper part insted.
+        if (array[middle] < key) {
+            first = middle + 1;
+        }
+        // the middle value is equal to wanted value
+        else if (array[middle] == key) {
+            return middle;
+        }
+        // the middle value is bigger than wanted key
+        // search lower part insted.
+        else {
+            last = middle - 1;
+        }
+
+        middle = (first + last) / 2;
+    }
+
+    // didn't find key
+    return Number.NEGATIVE_INFINITY;
+}
+
+sampleArray = [1, 2, 3, 4, 5, 6];
+sampleKey = 2;
+
+console.log(binarySearch(sampleArray, sampleKey));