Merge pull request #28 from srinjoy07pal/master

Update BinarySearch.java

Author: learning-zone

core-java/basics/BinarySearch.java

@@ -1,19 +1,47 @@
-package basics;
-import java.util.Arrays;
-
-public class BinarySearch {
-
-public static void main(String[] args) {
-
-int arr[] = {10, 20, 15, 22, 35};
-Arrays.sort(arr);
-
-int key = 35;
-int res = Arrays.binarySearch(arr, key);
-if(res >= 0){
-System.out.println(key + " found at index = "+ res);
-} else {
-System.out.println(key + " not found");
-} 
+// Java implementation of iterative Binary Search
+
+import java.io.*;
+
+class BinarySearch {
+
+// Returns index of x if it is present in arr[].
+int binarySearch(int arr[], int x)
+{
+int l = 0, r = arr.length - 1;
+while (l <= r) {
+int m = l + (r - l) / 2;
+
+// Check if x is present at mid
+if (arr[m] == x)
+return m;
+
+// If x greater, ignore left half
+if (arr[m] < x)
+l = m + 1;
+
+// If x is smaller, ignore right half
+else
+r = m - 1;
+}
+
+// If we reach here, then element was
+// not present
+return -1;
+}
+
+// Driver code
+public static void main(String args[])
+{
+BinarySearch ob = new BinarySearch();
+int arr[] = { 2, 3, 4, 10, 40 };
+int n = arr.length;
+int x = 10;
+int result = ob.binarySearch(arr, x);
+if (result == -1)
+System.out.println(
+"Element is not present in array");
+else
+System.out.println("Element is present at "
++ "index " + result);
 }
 }